oceanographic and meteorological aspects of the gulf of ...€¦ · gulf of california- roden!.~...

Oceanographic and Meteorological Aspectsof the Gulf of California!

GUNNAR 1. RODEN

THE PRIMARY OBJECT of the present paper isto give an adequate description of the climatic and oceanographic conditions in theGulf as they are known today .

Only a few authors have discussed theGulf (Sverdrup, 1940; Osorio Tafall, 1944)and only the geological work was describedin detail (Anderson, 1950; Durham, 1950;Natland, 1950; Revelle, 1950; Shephard,1950) .

The data used in the present investigationare largely taken from the "E. W. Scripps"expeditions in 1939 (Sverdrup and staff, 1943)and from the publications of the ServicioMereorologico Mexicano, the U. S. Coast andGeodetic Survey, and the U. S. HydrographicOffice.

The data for the Gulf are few and the conclusions that can be drawn from them arenecessarily limited and should be taken onlyas a first approximation until more and betterdata are at hand.

The Gulf of California is of considerableinterest both scientifically and economically,

1 Contribution of the Scripps Institution of Oceanography, New Series, No. 960. The work reported onherein represents results of research sponsored in partby the Office of Naval Research under contract withthe University of California. Manuscript received July24, 1956.

21

and it is expected that its importance willsteadily increase in the future, especially as anadditional food source for Mexico. A thorough knowledge of the physical and chemicalchanges taking place in the Gulf is essentialto the understanding of its fisheries.

Moreover, the Gulf is interesting becauseit represents the only large evaporation basinof the Pacific Ocean and because it showscertain differences from other comparableevaporation basins. A final answer to all thedifferent problems in the Gulf cannot beexpected from the meager data available butit is the hope of the author that this papermay stimulate more research in this intriguingarea.

ACKNOWLEDGEMENTS

The author is indebted to Dr. Warren S.Wooster and Dr. Robert S. Arthur for valuable help and suggestions that made thisstudy possible, to Mr. Joseph L. Reid, Jr.,Dr. F. Phleger, and Miss June G. Pattullo forreading the manuscript, to Mr. TownsendCromwell for a discussion on a definition ofa front, and to Sr. Enrique Avila for adviceon the writing of Spanish place names andother terms . The author also wishes to expresshis thanks to those who have helped him to

prepare the drawings .

22 PACIFIC SCIENCE, Vol. XII, January, 1958

FIG. 1. Bath ymetri c map of the Gulf of Californi a.

GENERAL DESCRIPTION AND PREVIO US

INVESTIGATIONS

The Gulf of California is unique in manyrespects. Lying as it does in a predominantlyarid region it comprises the only large evaporation basin of the Pacific Ocean . It is roughlyrectangular in shape and lies between theMexican states of Baja California to the westand of Sonora and Sinaloa to the east. At itssouthern end the Gulf is in open communication with the ocean . The length of the Gulfis about 1400 km . and the average widthabout 150 km., giving a total surface area ofroughly 210,000 km .", if the southern boundary is taken along latitude 23°N . Betweenthis latitude and a line joining Cabo SanLucas with Cabo Corrientes (Fig. 10) lies atransition region which occasionally is in-

fluenced by Gulf water (Schott , 1935). Thisregion will be called the Gulf Entrance, andit has a total surface area of roughly 40,000krn .t

Topographically the Gulf can be dividedinto a number of basins, separated from eachother by transverse ridges . The deepest basinshave a maximum depth of more than 3000m. .and a sill depth below 1500 m. (Geol.Soc. Amer. , Mem., 1950). In the northernpart of the Gulf isolated basins are found inwhich different hydrographic conditions prevail (Sverdrup, 1941) . These basins seem torepresent deep depressions in an otherwisequite narrow shelf and are completely isolatedbelow 200 to 300 m. Their isolated characteris quite sufficient to explain the hydrographicconditions found in them and it is not neces-

Gulf of California - RODEN

!.~

FIG. 1. Bathymetric map of the Gulf of Californi a (continued).

23

sary to assume the existence of a ridge running SSE between Angel de la Guarda andTiburon to account for the differences (Sverdrup, 1941). There are two large islands in theGulf-Angel de la Guarda and Tiburonboth with elevations exceeding 1500 m.

The coast along Baja California is verysteep and flanked by numerous islands androcks. Off Rio Colorado and northern Sonorathe coast is less rugged and possesses a wideshelf. Along Sinaloa the shelf narrows againand disappears at Cabo Corrientes .

The Gulf remained scientifically unknownuntil fairly recent times. Prior to the comingof the conquistadores, the Gulf area was inhabited by different Indian tribes who livedby fishing and undoubtedly had some localknowledge of the currents and the general

appearance of the water. Their observationsare, however, lost because they had no writtenrecords:

With the coming of the Spaniards, tradedeveloped between Gulf ports and the FarEast (Hakluyt, 1598) and various captainsentered the Gulf with lead and line. The firstwritten records are therefore found in theships' logs of the early seafarers. Scientificexploration began in 1889 when the U. S.Fish Commission steamer "Albatross" (Fig.2) entered the Gulf to make a few hydrographic stations, especially in the northernpart (Townsend, 1901). The data collected atthese stations consisted of temperature anddensity determinations, the latter being madewith a hydrometer. The results of the expedition (not previously published in this form)are shown in Figure 3.


"E W SCRIPPS " 1939 "E W SCRI PPS "1940 " AL BAT ROSS" 1889

FIG. 2. Stations occupied on previous expeditions.

Considerable warming and high salinitywere found in shallow bays such as BahiaGuaymas and Bahia Concepcion. Upwellingwas characteristic along the nor thern coast ofSonora where the temperature was abo ut onedegree lower and the salinity 004%

0 lower thanin the neighborhood offshore; Near the mouthof Rio Colorado the salinity varied between35.2 and 35.7% 0, probably due to the admixture of fresh water. The bottom temperatures in the northern part everywhere exceeded11"C. and the bottom salinity varied between35.5 and 36.1% 0.

The next important description of the Gulfof California was made by Thorade (1909) ina paper on the California Current. He examined a great number of ship logs over manyyears and was the first investigator to drawmonthly surface temperature charts (Fig . 4)

for the southern part of the Gulf and deducefrom them the general circulation in th e Gulfand to correlate the sea surface temperaturesto the direction of the wind , the orientationof the shore line, and the special climatological conditions prevailing in the Gulf. Hismain conclus ions were that the temperatureof the Gulf is independent of the temperatu rein the adjacent ocean and that the low tem peratures along the east coast in winter arethe result of northerly winds that tend totransport surface water away from th e coastand thus produce upwelling. He also observedcorrectly that dur ing most of the year thecirculation is counterclockwise in the Gulfand that the water enters the Gulf along theeast coast and leaves it alon g the west coast.He mentioned that "manifold discontinuitiesare observed by a. sudden change in tern-

Gulf of California- RODEN

WIND TEMP. (OC)

25

FIG. 3. Distribution of winds, temperature, and salinity in March , 1889.

perature" in the vicinity of Cabo San Lucas,which might well have been the first description of the San Lucas front.

Schott (1935: 208 ) described the Gulf ofCalifornia as part of the Mexican region, aregion defined roughly as lying between theGulf of Tehuantepec and Cabo San Lucas andextending seaward between the CaliforniaCurrent and the North Equatorial Current.The Mexican region is characterized by a veryhigh surface temperature and very weak circulation. He briefly mentioned the temperature -disconrinuity near Cabo San Lucas anddrew attention to the frequent hurricanes inthat region .

In the spring of 1939 the Scripps Institutionof Oceanography sent an expedition into theGulf led by H . u. Sverdrup on the "E . W.Scripps." Fifty-three stations were made in the

Gulf (Fig . 2) taking temperature, salinity,oxygen, calcium carbonate and plankton observations on each station from the surface tothe bottom (Sverdrup and staff, 1943). Thesedata are still the most complete ever takenin the Gulf. Sverdrup's main conclusions werethat the Gulf can be subdivided into twoparts, a northern part and a southern part,separated from each other by a submarineridge which comes to within 200 m. belowthe surface. The water mass to the north islargely of local origin and formed by convective currents in winter, the water to thesouth is nearly the same as in the adjacentocean and only modified slightly at the surface by extensive evaporation (Sverdrup,1941).

In late fall of 1940 the "E. W. Scripps"made a second trip to the Gulf. The chief


SEPT.

16

FIG. 4. Sea surface temperature s (0c.) in the Gulf of Californi a. (After Th orade, 1909.)

aim was geological (G eol. Soc. Amer., Mem.,1950) but a few hydrographic stations weremade (Fig . 2) . Silicate and phosphate weremeasured for the first time in the Gulf, bu tthe methods used in determining th e concentrations do not warrant a de tailed description of them. A brief. account on the silicatedistribution in the Gulf was given by Sverdrup (Sverdrup and staff, 1940) . In 1944 theMexican government sponsored a brief study

of the Gulf in order to determine the feasibil

ity of a minor guano industry (Osor io Tafall,

1944). The industry was never started . In 1956the U . S. Fish and Wildlife Service has planned

two expeditions into the Gulf to study the

distribution of sardine eggs and larvae and tomake frequent hydrographic stations, which

un doubtedly will bring back new and valu able data for further scient ific investigations.

Gulf of California - RODEN 27

CLIMATOLOGY

The great differences in climatic conditionsobserved in the Gulf as one proceeds fromnorthwest to southeast, covering nearly ninedegrees of latitude, and the differences thatexist between the east side and the west sideof the Gulf, are closely related to the atmospheric circulation and to the existence ofmountain ranges that modify this circulation.

The influence of the Pacific Ocean uponthe climate of the Gulf is greatly reduced bya nearly unbroken chain of mountains, 2000to 3000 m. high , in Baja California. The considerable differences in temperatures and precipitation between the Pacific side and theGulf side have already been mentioned byTh orade (1909) and are fully confirmed bydata collected by the Servicio MeterologicoM exicano (Bolerin Anual) . Along the Pacificside of the peninsula the air temperatures arenever excessively high and precipitation fallsduring the winter season in the northern part,and during the summer season inthe southernpart , with annu al amounts around 200 mm .Along the Gulf side air temperatures are veryhigh in summer and rather cool in winter. In

the north all the precipitation falls in sum mer. The amount of rainfall (Table 1) variesbetween traces in the north and 200 mm . atthe southern tip of Baja California, which iscrossed by the Tropic of Cancer. The rainfallon the corresponding latitude on the easternside of the Gulf amounts to 400 mm . per year.

On the average the west coast of the Gulf'receives only half as much rain as rhe eastcoast. In Sonora the winter is cool and thesummer hot. Precipitation falls from July toSeptember, varying between traces in thenorthernmost part and 251 mm. in Guaymas.In Sinaloa the winter is warm and the summerless hot than in Sonora. Precipitation fallsfrom August to October, with amounts between 300 mm . in the north and 850 mm . inMaz atlan (Table 1) . From the discussion ofthe precipitation figures it becomes evidentthat the Gulf of California is far from beingsitu ated in a desertli ke environmenr.f Thevegetation in Baja California and Sonora is of

2 M ost Americans call northern Son ora and BajaCalifornia a de sert, th o ugh peop le fro m N orth Afri caand South America would cons ider this regi on a dr ysteppe. .

TABLE 1M EAN M ONTHLY AIR T EMPERATURE AND PRECIPITATION 1921-1935 (SERV M ET MEX BOLETIN ANUAL).,

WEST COAST (IN GULF) EAST COAST (IN GULF) EAST COAST (OUTSIDE GULF)

Cab oMulege La Paz Guaymas T opolobam po Mazatlan Corrientes

(26°53'N- (24°lO'N - (27°55'N - (25°36' N- (23°11'N - (200 24' N-112°00'W) 110018'W ) 1100 53'W) 109°03'W) 106°25'W) 105°43'W)

-Temp. Prec. Te m p. Pree. Temp. Pre e. Temp. Prec. Temp . Prec. Temp. Prec.dc. mm. DC. mrn. DC. mm . DC. mm. DC. mm. DC. m m .

January . . . 14.0 2.6 18.2 3.2 17.7 7.9 18.6 6.4 19.3 11.0 23.2 19.5February .. 16.0 3.4 19.2 11.4 18.9 6.3 19.7 6.6 19.4 9.7 22.9 29.6M arch . . .. 17.8 0.1 21.3 0.8 20.7 4.6 20.1 6.4 19.7 3.4 22.7 1.3April. .. .. . 20.1 0.2 23.2 0.2 22.8 3.0 22.2 tr. 21.3 0.1 23.9 tr.M ay .. . . . . 22.9 0.1 25.5 rr. 25.5 2.8 25.0 1.8 23.8 1.8 25.4 2.3J une . . .... 27.2 tr. 27.2 0.2 28.8 0.7 29.1 5.3 26.4 29.2 26.7 57.3J uly . .. . .. 30.5 6.1 30.0 6.3 30.7 46.7 29.8 39.9 27.5 166.9 28.9 145.0Au gu st .. . . 30.4 16.8 30.3 41.7 30.5 75.5 29.7 100.6 27.6 241.8 27.9 272.1September. 29.0 40.0 29.0 51.9 30.2 54.4 29.7 55.9 27.5 268.6 27.5 307.0October .. . 24.6 5.4' 27.0 9.6 27.3 9.5 27.8 73.7 26.7 61.6 27.5 91.0N ovember . 19.5 6.8 23.2 13.4 22.6 11.1 24.0 7.0 23.5 11.7 26.1 15.2D ecem ber. 14.9 19.2 20.0 34.3 18.6 28.9 19.7 55.3 20.6 44 .4 23.8 13.5year .... . . 22.2 lOLl 24.4 173.0 24.5 251.4 24.6 358.9 23.6 850.2 25.5 953.8M inimum . 0.0 - 0.0 - 7.0 - 8.0 - 11.2 - 12.0 -M aximum. 41.9 - 40.5 - 47.0 - 4Ll - 33.4 - 43.8 -


<,-,

\\\\\\\\

IX X XI XII

/r- .....

/ \'I \

\\\\\\\\\\\\

/--::--.../ ~

LA PAZ //

//

//

/AIR"j/

/ ~SEA

//

GUAYMAS

20

20

18

22

24

26

28

16

18

oa,

30°CWa:~ 28l-e::{a: 26Wa.. 24~WI- 22

26

24

22

20

,MAZATLAN

//

//

//~AIR

" ,/" ------18

Gulf of California- RODEN 29

the dry steppe type, and in southern Sinaloait is tropical.

The distribution of air temperatures (Fig.5) shows a temperature minimum in Januaryand February and a maximum in August andSeptember. The annu al range in temperaturesincreases from south to north and is some what greater along the coast of Baja Californiathan along Sonora and Sinaloa . The meanannual range at the entrance is around lODe.and in the northernmost part about 20°e. Theextreme annual range (Table 1) is approximately twice the average annual range (Serv.Met. Me x., Boletin Anual ) . In general the airis warmer than the sea during the first half ofthe year and cooler during the second, exceptfor Mazatlan, where the air is always coolerthan the sea (Fig . 5).

The distribution of winds (Table 2) showstha t the monthly average wind velocities are

quite low, lying between 1.5 m/sec and 6.1m/sec. The higher values are found in winterand spring. The direction of winds varies withseason and with distance from the entrance.D uring winter, northerly winds are predominant in the entire Gu lf, but in summer thesouthern half of the Gulf is mostly influencedby southerly winds . In the northern half,southerly winds blow only one or two monthsof a year.

Winter gales of short duration, locallyknown as chubascos, are frequent and velocities may occasionally reach 30 m/sec.

Hurricanes are not as rare in the Gulf as isgenerally believed . Between 1910 and 1930thirty-nine were registered (Schott, 1935:280) . These hurricanes, known as " EI Cordonazo," may enter the Gulf any time between May and November, but are mos tfrequent in September and October (Fig . 6).

--------31.VII- 7. VIII

4 . IX - lO.IX

19.X - 26 .X

26.X- 28 .X

LEGENDA

15°---t------t----~~~:....:=__+-- --+~

200 - - - f-- - - -If---l{--3...-il'll

25~---i---\

FIG. 6. Paths of hurric anes in 1936. (After ServoMet. Mex ., Boletin Anu al, 1936.)

30

TABLE 2M EAN M ONTHLY WIND VELOCITY IN LA PAZ,

G UAYMAS, AND M AZATLAN(Serv. Met. M ex., Boletin An ual)

LA PAZ GUAYMAS MAZATLAN

mfsec mfsec m/sec

J anu ary . . . . . . . 2.6 4.8 6.1February . . . . . . 2.4 4.2 5.9M arch . . . . . . . . 2.2 5.3 5.5April . . . . .. ... 2.3 5.1 5.0 ;M ay... . . . . . .. 2.1 4.6 4.8J une .. . . .. . . .. 2.4 4.3 4.6July . . . . . . . . . . 2.0 3.5 4.3August .. . . . . . 2.0 3.6 4.9Sept emb er. .. . . 1.5 4.4 5.0O ctober . . . . . . . 1.8 4.8 5.1N ovember. . . . . 2.3 4.6 4.1December. . . . . 2.3 4.9 5.5Yea r. . . . ..... . 2.2 4.5 5.1

In La Paz winds are northerly from November untilM arch and southerly from Ap ril until O cto ber.

In Guaymas win ds are northerly from Augu st untilM ay and southerly in J une and July. onl y.

In M azatlan winds are northerly from Novemberuntil Apr il and westerly from M ay until O ctober.

They originate in th e Caribbean Sea or off thecoast of Central America and it takes thembetween five to seven days to reach the Gulf(Serv. Met. Me x., Boletin Anu al).

If one compares th e distribution of windsand the occurrence of the rainy season withthe migrating low pressure system over western Mexico (Fig . 7) it is seen that northerlywinds are found with the low pressure to theeast , and southerly winds with the low pressure to the northwest. Th e beginnin g of therainy season is connected with th e appearanceof southerly winds th at carry moist air intothe Gulf and give rise to uplift rain.

Evaporation is one of the mo st importantfactors in the Gulf and is responsible for thehigh salinity observed in the surface layers.The amount of evaporation has been determined from pan observations at a few shorestations (Serv. Met. Mex., Boletin Anual ).These measurements show a main maximumin summer and a main minimum in winter.The amount of annual evaporation varies between 1800 mm. in La Paz and about 3000

PACIFIC SCIENCE, Vol. XII, January, 1958

mm . in Gu aymas (Table 3). The values areconsistent from year to year for each stationand the deviations from the above values aregenerally less than 10 per cent (Serv. Met.Me x., Boletin Anual ).

Since evaporation from pans is not strictlyrepresentative for evaporation from the seasurface, it is of interest to see how the ob served evaporation from pans compares toevaporation derived from indirect methods.

The use of the energy bud get meth od isrestricted, because the advection term cannotbe evaluated.

In the meteorological approach a straightline relationship between the evaporation , E,and the produ ct of wind . velociry, W, andvapor pressure difference , .1e, is assumed(Jacobs, 1951) ; the coeficient of proportionality depen ds upon the height where the windvelocity and the humidity has been measured,and upon the roughness of the sea surface.In the following the coeficient of proportionality will be taken as 4.26 (Jacobs , 1951)so that

E = 4.26 W.1ewhere E is in mm /rn onth, Win m/ sec, and.1e is in mb.

A comparison between the pan and compu ted evaporation for th e year 1938 is shownin Table 3, and it is readily seen th at notabledifferences exist . Th e computed evaporationis less than the observed evaporation (Fig . 8)for La Paz and Mazatlan . In La Paz the maximum evaporation occurs in summer and themin imum in winter; in Mazatlan the observedevaporation shows a winter min imum and asummer maximum, whereas the computedevaporation has a summer minimum and afall maximum. The summer minimum is dueto the low wind velocities observed durin gth is season . Values for Guaymas are notstrictly comparable because the pan observations were made on a nearby station fartherinland; neverthel ess it is int eresting to noteth at th ere the total annual amount of evaporation is considerably higher than in La Paz orM azatlan.

Gulf of California - R ODEN 31

2 OO---t-------'+-----'~.----+-

25°--+---T-\--+-"'d----'\___+_

200 - --t- - - - - +---f'----'\<-- t-

MARCH JU LYFIG. 7. Position of the low pressure in M arch and July, and resulting winds .

TABLE 3MEAN MONTHLY EVAPORATION

Eo = measured from pans, Eo = computed

LA PAZ (1938) GUAYMAS (1943) MAZATLAN (1938)

Eo Eo Eo Eo Eo Eo

mm . mm . mm . mm. mm . mm .

J anu ary . . . . .. . . . . . . .. . 139 76 139 174 185 172Febru ary . . . . .. . . . . . . . . 120 41 206 216 213 194March . . . . .. . . . . . ... . . 129 81 286 269 148 129April. ... .. . . . . . . . ... . 119 98 351 276 205 133M ay . . . . . . . ...... . . .. . 146 127 446 337 210 163June . . .. . .. . .. . . .. . . . . 166 126 420 299 211 130July . . . . . . .. . . . . . . .. . . 174 172 294 280 230 123August .. . ..... ... .. . . 197 156 246 239 289 181September. . .. . .. . . . . . . 150 82 198 266 202 190October. . .. . . .. . . . . .. . 159 180 162 337 210 245November . . . . .. . . . . . . . 158 98 148 178 162 196December . . . . .. . . ... . . 154 57 92 288 140 196year . . . . ... . . .. .. . .. . . 1809 1294 2958 3247 2492 2071

(Eoj Ep)year . .. . . . . . . .. . 0.72 (1.10) 0.83


XII I I III IVMONTHV VI VI I

PAN

-,'COMP

-LA PAZ

GUAYMAS

-zz.:»:_...----,-_...-"'-

400mm

o

200

300

Z 100ot-<t

~ 200mma..<t 10 0>W

300mm

200

10 0

,MAZATLAN

'-'1..../_,_ COMP,--PAN

FIG. 8. Computed evaporation (Es) and pan evaporation (Es),

The difference, evaporation minus precipitation, has a maximum in early summer, aminimum during the rainy season , and asecondary maximum immediately after therainy season . Except for Mazatlan durin g thepeak of the rainy season , evaporation exceedsprecipitation during all months of the year.The few available data indic ate th at the meanannual evaporation for the sou thern half of theGulf lies between 1500 and 3000 mm . For theentire Gulf, considering the dry northern part,roughly 2500 mm. can be taken as a con servative estimate for the mean yearly evaporation. With this value the rate of evaporation

over the entire surface of the Gulf becomes5.25 x 1QlIm3/year or 1.7 x 1Q4m3/ sec.

GENE RAL CIRCU LATION

The bulk of water in and near the Gulf ofCalifornia is the same as in the equa torialPacific, slightly modified at the surface byextensive evaporation and by th e admixturewith water brought south by the CaliforniaCurrent. The influence of the latter is restricted to the vicinit y of Cabo San Lucas.

The gteat similarity between the Gulf andPacific Equatorial water, below the thermocline, is illustrated by the close agreement

Gulf of California- R ODEN

between the temperature-salinity relationshipsfor either water mass (Fig. 9). Points for theGulf were obtained from the " E. W . Scripps"expedition in 1939 (Sverdrup and staff, 1943).The solid curves represent the limits fortypical Gulf water, the dashed curves showthe limits for the equatorial Pacific (Sverdrupet al., 1942: 741).

It is seen that a nearly straight line relationship exists between the points 16°C., 35.2% 0and 9°C., 34.6% 0. The salinity minimum liesin both cases between 34.5 and 34.6% 0 andhas a corresponding temperature of between5°C. and 7°C.

The circulation in the Gulf is rather complicated and not fully understood. In winter(Fig. 10) outflow takes place at the surfaceand inflow at greater depths, in summer (Fig .11) the situation is reversed. Thorade (1909)mentioned one case of oppositely runningcurrents at the surface and at 40 m. near thecoast of central Baja California .

In the northern part of the Gu lf cooling ofhigh saline water in winter leads to the formation of a bottom water mass (Sverdrup, 1941),which is characterized by a temperature above10°C. and a salinity above 34.9%0 and arelatively high oxygen content. This waterfills the isolated basins of the northern shelf

33

and moves southward along the coast of BajaCalifornia (Fig. 19).

Tidal currents are strong in _the northernthird of the Gu lf and may obtain velocitiesof several knots in the narrows between theislands and near the mouth of Rio Colorado.

The exchange between the G ulf and thePacific Ocean cannot be calculated accuratelyfrom the available data. It is, however, possible to get a rough estimate of the exchangeof water and salt across latitude 23°N assum ing conservation of these properties. If Edenotes the rate of evaporation and if S, Soand Qb Qo represent the salinity and amountof the in- and outflowing water, respectively,the following equations hold (Sverdrup et al.,1942: 148)

So s,Qi = - - - E Qo = --E.

So - S, So - Si4 .

Taking E as 1.7 X 10 m3/sec (see above), S,as 34.6%0 and So as 35.1% 0 one gets:

Qi = 1.19 X 106 (m3/ sec)Qo = 1.17 X 106 (my sec).

It is seen that evaporation plays only anegligible part in the general circulation ofthe G ulf, and that inflow very nearly balancesoutflow. If one assumes that the outflowing

0° 10°

TEMPERATURE (Oel20°

enl>rz-i-<

FIG. 9. Temperature-salinity diagram for the Gulf (solid lines) and for the equatorial Pacific (dashed lines).


110° 105° 100° 95· 90·W

SALINA CRUZ

FEBRUARY

t""-t.?'.j.~~J

" <- <-,, """"-.'c-.j.

'" <- . <'- ~ <- ...... <- ,J.

ACAPULCO

""" ",...,.~~ ....,."'" " 'II" J

tt t

J, \ ? MAZATLAN

C. SAN LUCA

-e--' "'" ,,( J ,J.,J. ,J. '.

~"""KJ ...... ,J.,J.~ !J t t .; .j. - ,J.,J. .j. C. CORRIENTES

,,<- - -<--<-.; .; I...-'/ ,,(j,("<'- e-' -t,J. t,/~

",,"-.'\ \....- '(,,(-\.'3\,

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'\._<-<-<,- ...... 115 °

e-: "it

'\ tt

-s-,

10 °

115°

3 0 0 N

1-- -20°

1--- - 25° - +----1,.

FIG. 10. Surface currents in February. (After U. S. Hydrog. Off., 1947.)

water extends over a depth range of 50 m.and inflowing over 1500 m., across latitude23°N, the velocity of the ou tflowing wateris 7 em/sec and of the inflowing water 0.3em/sec. This calculation holds only for winter, when northerly winds are responsible foroutflow at the surface.

The influence of the Gulf of Californiaupon the adjacent Pacific Ocean is small(Sverdrup et al., 1942: 732) and varies withseason. The influence is greatest in winterwhen strong northerly winds drive the surfacelayers out of the Gulf and least in summerwhen southerly winds drive oceanic water intothe Gulf. The exact distance seaward from theentrance of the Gulf that Gulf water can bedetected (by its higher salinity) is not known.

The circulation in the vicinity of the Gulfof California is affected by the water carried

south by the California Current and by thewater found off Mexico and Central America.The former is characterized by a low temperature, a low salinity, and a rather high oxyge ncontent, whereas the latter has a very hightemperature at the surface and a very lowoxygen content below the thermocline (Sverdrup et al., 1942: 730). Between both lies atransition region which, 500 miles to thewest, is found approximately between latitudes 17°N and 200N (Wooster and Cromwell, verbal communication) .

In February (Fig. 10) the coastal surfacecirculation (U. S. Hydrog. Off., 1947) ischaracterized by southward currents north ofabou t latitude 200N and by westward flowingcurrents south of this latitude. An interestingfeature is a large gyre off the southern coastof Mexico which is maintained by strong

Gulf of California- RODEN

- - 30·N - ---'c----\

25 · .J, .\-

.f ~

J. J 1/ MAZ ATLAN

~ J '" 1C 1C JU LV

35

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t .\- .J.1/ '\ <, K -<-- ..... '\ <, '" e-, +- ...... - ...... e-: <, <-15· r '\ '\<'-..J. e-: '\ +- ~ f' r '\ <, +- <, .,.. .....

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V" ..... " ,, "'-,j.

~

~ » <:.. <, k" YO<--'\. +-- ...... <, '\ "'- '\ <,

...... r '\ '\ -<-- -<-- ..- -<-- +- +- ............. ................... <, <,

10·

115· 110· 105· 100· 95· 90 · W

FIG. 11. Surface current s in]uly. (After U. S. Hydrog. Off., 1947.)

northerly winds blowing into the Gulf ofTehuantepec. This gyre is strictly a winterphenomenon and ceases as soon as the windsin the Gulf of Tehuantepec change theirdirection .

InJuly (Fig. 11) a current flows nort h alongthe coast of Mexico and enters the Gulf ofCalifornia. The entire current pattern east of1100 W is characterized by a slowly west tonorthwest moving water mass. West of thislongitude the current is toward the southnorth of latitude 200 N and toward the westsou th of this lati tude .

The monthly average speeds of these cur. rents are low and lie almost entirely within5 ern/ sec and 20 ern/ sec.

FRONTS IN THE VICINITY OF THE GULF

In the following the term "front" will be

used as suggested by Cromwell and Reid(1956), i.e., as a narrow band along the seasurface across which the density changesabruptly. The terms "temperature front" and"salinity front" will be used to describe thedensit y front, since it is only from temperature and salinity measurements that the density can be adequately determined. The definitecharacter of a front can only be establishedif continuous temperature and salinity recordsare available. Unfortunately there are no continuous records of salinity , for which reasona description of the fronts in the vicinity ofthe Gulf must be based on closely .pacedstations rather than upon continuous records.

Two regions of rapid temperature and salinity transit ion have been found to exist in theGulf Entrance, one off Cabo San Lucas andone off Cabo Corrientes (Fig. 12). The San

36

Lucas transition represents a very sharp boundary between warm and high-saline Gulfwater, and cool , low-saline water from theCalifornia region. It was first described byThorade (1909), who pointed out that theintensity of the front is seasonal in characterand that the maximum intensity occurs inlate spring when the temperature differencesbetween the Gulf and California Current waterare greatest.

The San Lucas front is illustrated in Figure13 (unpublished data ). It is seen that thefront is marked by a narrow band across whichthe temperature decreases from 21° to l S°C.and the salinity from 34.6 to 34.1%

0 •

It is possible that when the more salineGulf water is cooled rapidly some sinking ofthis water takes place at the front , but this


feature has not been investigated. The ternperature structure below the San Lucas frontis shown in Figure 14. The bathythermographsection from Cabo Corrientes to Cabo SanLucas was prepared from hourly temperatureobservations made aboard the U. S. vessel"Golden Bear" and led to the discovery ofanother front in the vicinity of Cabo Corrientes. It is seen that the temperature differences across the front increase with increasingdepth. The increase could be explained as theresult of decreased mixin g at greater depth,but the feature needs further invest igation.

Since the winds were nort herly in April,1949, when the " Golden Bear" crossed theGulf Entrance it can be assumed that analready warmed water mass was driven out ofthe Gulf and pushed the cooler water north

-+---25°---+---------+----1

-t--- 2 a° -----f--------f----==-------fi------#--', C. CORRI ENTES

I--f---- 15°

110°

FIG. 12 . Ob served fronts (solid black) and transition regions (shaded) near the Gulf of California.

Gulf of California - R ODEN 37

•LA PAZ

TEMPERATURE (OC) SALINITY (%0)FIG. 13. Surface appearance of the San Lucas front .

of Cabo San Lucas and ' south of Cabo Corrienres aside, thus giving rise to the frontsobserved .

U PWELLING

Upwelling in the Gu lf can be expectedalong the east coast with northerly winds andalong the west coast with. southerly winds .So far only upwelling along the east coast

has been investigated (Allen, 1937).The upwelled water is characterized by a

low temperature and a low salinity when compared to the temperature and salinity of thesurroundings. The surface oxygen content ofthe water is not necessarily a good indicatorof upwelling, since it is strongly influencedby phytoplankton productivity, and by exchange with the atmosphere.

10

(/)

~ 15t-l>J

~ 20

:::I: 2 5t-Q.

l>J0 3 0

35

40

TEMPEkATURE (OC)2'·N 2Z-N

1.·

• 0

CORRI ENT ES FRONT SAN LUCAS FRONT

FIG. 14. Bathy thermograph section from Cabo Corrientes to Cabo San Lucas, April, 1949.


Upwelling is not uniformly distrib utedalong the east coast with northerly winds butseems rather to be confined to certain places.Such places are in the lee of Isla Tiburon, inBahia Guaymas, in Bahia Yavaros and in thevicinity of Topolobampo (Allen, 1937). It isinteresting to note that all these places are inthe lee of islands or headlands, which suggests that upwelling is largely controlled bythe irregularities of the coast line as well asby the winds.

Upwelling is important in the Gulf as ameans of replen ishing the depleted surfacelayers with plant nutrients from below . Thereare, unfortunately, no data on the concentration of plant nutrients available for the regions where upwelling occurs , and it is forthe time bein g not possible to investigate thebiolo gical role of upwelling in a quant itativemanner. The high concentration of phytoplankton in the upwelling areas in spring(Allen , 1937) is indicative , however, of asufficient concentration in plant nu trients tosupport the large stan ding crop.

It should be pointed out th at upwelling isnot the only process to fertilize the surfacelayers with plant nutrients. Increased windmixin g and winter convection may be ofequal importance . The latter proces s is effec-

tive in the northernmost part of the Gulf(Sverdrup , 1941) whereas the former is beneficial everywhere . .

SEASON AL VARIATION OF T EMPERAT URE

AND SALIN ITY IN THE GULF

Information on the monthly variation oftemperature and salinity at the sea surface inthe Gulf is very scanty .

The first attempt to draw charts of monthlyaverage sea surface temperatures was made byThorade (1909) . He collected data from ships 'ob servations for many years and averagedthem. These pre-World War I charts are stillthe only ones in existence (Fig. 3). Since theSecond World War the U. S. Coast and Geodetic Survey has published sea surface tem peratures from a few shore stations in theGulf. These are given in Table 4. It is seenth at the min imum temperatures occur in J anuary and February and the maximum temperatures in August and September. The meanannual range lies between 23°C. and 28°C. inMazatlan and between 16°C. and 32°C. inGuaymas. In the northern half of th e Gulf

.the mean monthly temperatures are not kn own.The minimum in the northernmost part seemsto be above lO°C. since this is the temperatureof the bottom water found there (Sverdrup,1941).

T ABLE 4M ONTHLY VARIATION OF SEA W ATER T EMPERATURE AND SALINITY FOR LA PAZ, G UAYMAS, AND M AZATUN

(USCG S 1951, Schott, 1935)

LA PAZ GUAYMAS MAZATLA N

t°c. 50/ 0 0 t°c. 50

/ 0 0 t°c. 50/ 0 0

J anu ary . .. . .. ... . . . . . . 19.1 35.5 16.3 36.2 24.0 34.8Febru ary .. . . . .. . ...... 19.3 35.8 17.6 36.0 23.0 34.9M arch . . .. . . . . . . . . . . . . 20.0 36.4 18.2 35.8 24.0 35.0April. . . . . .. . . . . . .. . . . 22.0 36.6 21.0 36.2 24.5 35.1M ay . . . . . . . . . . . . . . . . . . 24.4 36.6 24.8 36.4 25.5 35.5une .. . .. . . . . ... .. . . . . 26.0 36.4 29.3 37.0 26.7 35.8uly . . . . . . . . . . . . . . . . . . 28.2 36.6 31.7 37.1 27.5 34.8

Augu st . . ... . . . . .. . .. . 29.8 36.2 31.4 36.3 28.2 34.6September . . . ... .... .. . 29.0 36.2 31.9 36.3 28.0 32.8O crober . . . . . .. .. . . . . . . 28.3 36.2 30.0 36.7 27.8 34.5November. . .. . . . . . . . . . 24.7 35.9 25.4 36.2 26.9 35.1D ecember . . . . .. . . . . . . . 21.2 35.7 19.6 36.2 26. 1 35.0year .. . . . . . . . ... . . . . . . 24.3 36.2 24.8 36.3 26.0 34.9M inimum ...... ... . . . . 17.8 34.1 11.0 31.4 - ILlM aximum . .. . . .. . . . . . . 33.3 40.4 36.2 41.0 - 36.7

JJ


The mean annual surface temperature isquite high in the Gulf and ties around 24°C.(Table 4). In Mazatlan the mean annua l temperature is very high (26.0) and the surfacewater there is probably of advective origin,because it is always warmer than the air aboveit (Fig . 5).

Mean monthly salinities (USCGS 1951) arelisted in Table 4. The salinity (Fig. 15) hastwo maxima and two minima. The first maxi-

39

mum is found around J une and is the resultof excessive evaporation. With the comingof the rainy season the salinity of the surfacewater falls and reaches a minimum at the peakof the rainy season . In October increasingwinds and rapidly decreasing air temperaturesand the lack of large precipitation give riseto a second peak in net evaporation which isalso reflected in the second salinity maximum.After the October maximum the salinity de-

E- p {mm)

400

300

200 E- P

S%o

»<> 37

,/ " ---__~L. _..... '___ --

--,_-- 36

z E-p{mm)

~ 200t-e:( 10 00:oa. 0e:(

>W

tWZ

E-p {mm)

200

10 0

o

-100

LA PAZ

,--- -----..--------.......-../' ......._----/" ........

,-SAL. /' -_---/

MAZATLANE-P~_- __

---/

'\ /\ /\.//

FIG. 15. N et evaporation and salinity for Gu aymas, La Paz, and Ma zatlan.

en»rz

S%o =i36 -<

35

S%o

35

34

33

40

creases and reaches a second minimum aroundD ecember. The salinity ranges between 35.5and 36.5%

0 in La Paz and between 35.8 and37.1% 0 in Guaymas . Both places are situatedat the head of shallow bays where evaporationis extensive . Thes e values are, therefore, notrepresentative for the open Gulf.

In Mazatlan the salinity varies between 32.8and 35.8%

0 . The very low value found inSeptember (32.8%0) is possibly caused byextensive runoff from Rio Presidio duri ng theramy season.

Figure 15 illustrates that there is a, verygood agreement between net evaporation andsalinity. The slight differences seen can beattr ibuted to the different years in which thesalinity was observed and for which the netevaporation was computed .

DISTRIBUTION OF PHYSICAL AND CHEMICAL

PROPERTIES IN THE GULF

A preliminary discussion of the distributionof temperature, salinity, and oxygen in February and March, 1939, was pub lished bySverdrup (1941). A shor t repor t on the distrib ution of silicate and phosphate from October to December, 1940, was given by thesame author (Sverdrup and staff, 1940). Hereonly a few conclusions will be drawn from thedistribution of these properties. The distr ibu tion of phosphate and silicate in the G ulf canbe discussed only qualitatively, because themeasured data are such that they do no t warrant a quantitative discussion.

Vertical Distribution

The Gulf can be divided vertically into ashallow upper layer (20 to 40 m. deep) wherethe distrib ution of properties is rather uniformdue to wind stirring; a layer between roughly50 and 150 m., varying with season, where thetemperature , salinity and oxygen content decrease rapidly; and a deep layer, between thethermocline and the bottom, where th e concentrations remain fairly constant from oneseason to another.


In the upper layer the concentrations varyconsiderably with time due to the amou nt ofheating, cooling , stirring, evaporation,' precipitation, runoff and various biological activities. Shallow and semi-enclosed bays showgreater variations than the open Gulf. Thelayer of rapid density increase is generallycloser to the surface during the warm seasonth an during the cold season, but the availabledata are too few to give accurate depth ranges.Below the layer of rapid density increase thetemp erature decreases more or less slowlytoward the bottom, but in a few deep basins ,below 2000 m. , a slight increase is observeddue to the adiabatic effect.

The salinity shows a minimum (34.4834.54%

0 ) between 600 and 800 m. and increases slightly toward the bottom.

The amount of dissolved oxygen has a verypronounced minimum (less tha n 0.1 mljl)between 300 and 700 m. and increases againtoward the bottom.

The silicate content increases with depthand equals about 160 Jlg- at/l in the centralpart of the Gulf where the bottom depositsare largely diatomaceous oo zes.

Horizontal Distribution

The horizontal distributions .of tempera ture, salini ty and oxygen in February andM arch, 1939, are illustrated in Figures 16, 17,18 and 19.

At the surface (Figs. 16 and 17) the distribution of these properties is very complicated.The high oxygen values (more than 50 percent supersa tura ted in places) are probablythe result of extensive phytoplankton production. The southern half of the Gulf isslightly undersaturated with respect to oxygen. Upwell ing as indicated by a low temperature (and salinity) can be seen to occurin Bahia Guaymas and Topolobampo.

At subsurface depths (Figs. 18 and 19) thetwo outstanding features are a ton gue ofwarm, high saline and oxygen-rich water moving to the south along the coast of BajaCalifornia and a tongue of low saline, cool


WIND

41

SAL. (%0)

FIG. 16. Distribution of wind temperature and salinity at the sea surface in February and March, 1939.

and oxygen-poor water entering the Gulf fromthe south. The tongue along Baja Californiahas possibly its origin in the northern part ofthe Gulf, because it is of nearly the sametemperature, salinity and oxygen as the waterof the northern area. The inflowing watermass shows the same characteritsics as theequatorial Pacific water (Fig . 9) and representsa compensation flow to replace the water lostby evaporation and wind drift out of the Gulf.

CONCLUSIONS

The Gulf of California remains oceanographically unknown to a great extent. Theresults that have been presented here are based

on meager data and conclusions drawn fromsuch data may have to be modified when moreaccurate and more complete data are available.

Conditions in the Gulf are dependent uponthe conditions in the atmosphere and anychanges that take place in the atmospherewill also be reflected in the Gulf. The sub marine topography and the orientation of theshoreline also influence the circulat ion andhence the distribution of properties .

The bul k of the water found in the Gulfshows properties very similar to the PacificEquator ial water mass . This water mass uponentering the Gulf is modified at the surfaceby extensive evaporation which increases its

42

OXYGEN (mill)


OXYGEN SUPERSATURATION (°100)FIG. 17. Distribution of oxygen and oxyg en satur ation anomaly at the sea surface, in February and March, 1939.

salinity. The effect of evaporation increasesas one proceeds toward the northwest.

The circulation in the surface layers is predominantly wind driven. Since the windstransport water of different origin towards the

entrance of the Gulf, it is a transition regionmarked by the existence of fronts of whichthe San Lucas front is the best developed andbest known.

In the Gulf, as elsewhere , upwelling , sink-

Gulf of California - RODEN 43

OXYGEN (milL)

0.50 .1 ' , Q

tj.0.1 •

0 .0

SAL. (%0)TEMP. (Oe)

FIG. 18. Di stribution of temperature, salinity, and oxygen at 200 m. , in February and March, 1939.

ing , and con vective overturn play imp ortantparts in determining the fertilit y of any givenplace. Convection is especially conspic uous north of Isla Tiburon and is responsible for the different hydrographic conditionsthere. Upwelling is largely found in the leeof headl ands and islands, alon g the easterncoast with northerly wind s, and alon g thewestern coast with sou therl y winds . Awayfrom the shores the Gulf is fertile onl y inspring after con siderable winter mixing hasbrought an adequate supply of phosphatesand silicates to the surface. During the restof the year the surface waters are relativelybarren.

The field for investigations in the Gulf is

nearly unlimited and it is the hope of theauthor that in the future increasing effort s willbe directed towards the scientific explorationof one of the most fascinating seas in thePacific, the Gulf of California.

REFERENCES

ALLEN, W . E. 1923. Observations on surfacedistribution of marine diatoms of LowerCalifornia in 1921. Calif A cad. Sci., Proc.12: 437~42.

- - - 1937. Plankton diatoms of the Gulfof California obtained by th e G . AllanH ancock Expedition of 1936. The HancockPacific Expeditions, So. Calif Univ. Pub. 3:47- 59.

44 PACIFIC SCIENCE, Vol. XII , January, 1958

TEMP. (oG) SA L. (%0) OXYGEN (mill)

FIG. 19. D istribution of temperatur e, salinity, and oxygen at 400 m., in February and March, 1939.

--- 1938. The Templeton Crocker Expedition to the Gulf of California in 1935. Thephy top lankto n. A mer. Micros. Soc. T rans.67: 328-335.

ANDERSON, C. A. 1950. 1940 "E. W . Scripps"cruise to the Gulf of California. Part I :Geology of islands and neighboring lan dareas . Geo!. Soc. Amer., M em. 43: 1-5 2.

ANDERSON, E. R . 1953. The excha nge ofenergy between a body of water and theatmosphere with application in evaporation.Scripps Institution of Oceanography , Calif.Univ., Dissertation.

CROMWELL, T., and J. REID. 1956. A studyof oceanic fronts. Tellus.

D URHAM, J. W. 1950. 1940 "E . W. Scripps "cruise to the Gulf of California. Part II :M egascopic paleontology and ma rine stratigraphy. Geol. Soc. Amer., Mem. 43: 1-216.

GILBERT, J. Y ., and W. E. ALLEN. 1943. Thephyto plankton of the Gulf of Californiaobtained by the "E . W. Scripps" in 1939and 1940. Jour . M ar. Res. 5: 89-110.

H AKLUYT, R . 1598. The Principal Navigations,Voyages, Traffiques and Discoveries ofthe English Nation. Vol. 3. 397 pp . J. D ent andSons Ltd., London.

HOWARD, C. S. 1954. Composition of the Colorado River. Lake M ead Comprehensive Sur:vey, 1948-1949. Vol. 2. 165 pp .


J ACOBS, W . C. 1951. The energy exchangebetween sea and atmosphere and some ofits co nsequences. Scripps Institution of Oceanography, Bu]. 6: 27-122.

JOHNSTON, J. M . 1924. Expediti on of th eCalifo rnia Academy of Science to the G ulfin 1921. Calif Acad. Sci., Proc. 12: 9511218.

MUNK, W . H . 1941. In ternal waves in theGulf of California. J oftr. Mar . Res. 4: 81-91.

N ATLAND, M . 1. 1950 . 1940 "E. W . Scripps"Cruise to the G ulf of California. Part IV :Report on Pleistocene and Pliocene Foraminifera. Geol. Soc. Amer., Mem. 43: 1-55 .

O SORIO·TAFALL, B. F. 1943. El M ar de Cortesy la prod uc tividad fito plancronica de susaguas . An. de la Esc. Natl. de Cien . Bioi.3: 73- 118.

- - 1944. La expediti o n del M . N . " G racioso " po r aguas del extremo noroestemexicano. An. de la Esc. Nat!. de Cien. Bioi.3: 331-360.

PATTULLO,]., W. H . M UNK, and E. STRONG.1955. The seasonal oscillat ion in sea level.J our. Mar. Res. 14: 88- 156.

REVELLE, R . 1939. Sediments of the G ulf ofCalifo rnia. Geol. Soc. Amer. Bul. 50: 170, 171.

--- 1950. 1940 " E. W. Scripps" Crui seto the Gulf of California. Part V: Sedimentation and Oceanography. Geol. Soc.Amer., Mem. 43: 1-6.

SCHOTT, W . 1935. Geographie des Indiscben undStillen Ozeans. C. Boysen Ltd., H amburg.

413 Pl' .SHEPARD, F. P . 1950. 1940 "E. W . Scripps"

Cruise to the Gulf of California. Part II I :Submarine Top ography of the Gulf ofCalifornia. Geol. Soc. A mer., Mem. 43: 1- 32.

SMITHSONIAN INSTITUTE. 1951. SmithsonianMeteorological Tables. Washington, D . C.

SVERDRUP, H . D . 1940. The G ulf of California. ASJoc. Ocean. Ph.ys., Proc. Verb . 3: 170 ,171.

- -- 1941. The G ulf of California: Preliminary discussion of the cruise of the"E. W . Scripps " in February and M arch ,1939. 6th Pacific Sci. Congo Proc. 3: 161- 166.

45

SVERDRUP, H . D ., M . W . J OHNSON, andR . H . FLEMING. 1942. The Oceans. PrenticeH all, Inc., N ew York. 1087 pp

SVERDRUP, H . D ., and STAFF. 1940. Researchwithin physical oceanography and submarine geology at the Scripps Institu tionof Oceanography during April 1940 toApril 1941. Amer. Geophys. Soc., Trans. 21:490--495.

--- 1943. O ceanic observatio ns of theScripps Inst itution in 1939. Scripps Institution of Oceanography, Records of Observations1: 65-160.

TANNER, F. 1. 1889. Report o n inv estigationsof the D. S. Fish Comm ission Steamer" Albatro ss" for the year ending J une 20,1889. U. S. Fish Comn. Rept. for 1888. Pl'.395-5 12.

THORADE, H . 1909. Uber die KalifornischeM eeresstrornun g. Hydrog. U . Marit . Met.,A nn. 37: 17- 34, 63-76.

TOWNSEND, C. H . 1901. D redg ing and otherrecords of th e D . S. Fish CommissionSteamer "Albatross" with bibliography relative to th e wo rk of the vessel. U. S. FishComn. Rept. for 1900. Pl' . 387-562.

D . S. COAST AND G EODETIC SURVEY. 1951.Surface Water Temperatures at Tide Stations.Spec. Pu b. 280.

- -- 1954. Density of Sea-water of Tide Stations. Spec. Pub . 281.

--- 1956. Tide Tables: West Coast of Southand North America. Pub . 781.

D . S. G EOLOGICALSURVEY. 1950. SurfaceWaterSupply of the United States. Part 9: ColoradoRiller Basin. G eol. Survey, W ater SupplyPaper 1179.

U. S. HYDROGRAPHIC OFFICE. 1947. Atlas ofSurface Currents: Northeastern Pacific Ocean.Pu b. 570.

- - - 1951. Sailing Directions: lIVest Coast ofM exicoand Central America. Pub. 84. Charts619, 620, 621, 622,638,639, 640, 800, 849,850, 938, 1024, 1335, 1664, 1666, 1667,2087, 2103, 2130, 2181, 2193, 5388.

U. S. W EATHER BUREAU. 1950-52. Climato logical data . National Summary 1, 2, 3.

oceanographic and meteorological aspects of the gulf of ...€¦ · gulf of california- roden!.~...

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