Zinder team: Philippe Zinder team: Philippe CocquerezCocquerez, St, Stééphanie phanie VVéénel nel (CNES);(CNES);Jack Fox, Jack Fox, Terry HockTerry Hock, , Kieth Romberg Kieth Romberg (NCAR)(NCAR)

Paris team: Philippe Paris team: Philippe Drobinski Drobinski (IPSL/SA);(IPSL/SA);Dave Parsons, Dave Parsons, Joe VanAndelJoe VanAndel, Hal , Hal Cole Cole (NCAR)(NCAR)

Boulder team: Charlie Martin, Boulder team: Charlie Martin, Junhong WangJunhong Wang, Gary , Gary Granger, Dennis Granger, Dennis FlaniganFlanigan, Dean , Dean Lauritsen Lauritsen (NCAR)(NCAR)

Toulouse chef: JeanToulouse chef: Jean--Luc Luc RedelspergerRedelsperger

AMMAAMMA--THORPEXTHORPEXdriftsonde statusdriftsonde status

Special thanks to Albert Hertzog, Claude Basdevant & Rémy Roca (IPSL/LMD),Cheik Khane, Arona Diedhiou, Thierry Lebel (IRD), Peggy LeMone (NCAR)

and many others for assistance and fruitful discussions

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ATLANTIC OCEAN

~58,000 ft50 - 100 mb

Zero-pressureor

Super PressureBalloon

Gondola(20 to 50 sonde capacity)

SondesCommanded for Release

NORTHAMERICA

EUROPE

IRIDIUMLEO Satellite

System Concept

Cost-effective dropsonde observations of wind, temperature, and humidity to fill critical gaps in coverage over oceanic and remote artic and continental regions over days to weeks.

MIST Sonde and integration supported by NOAA/THORPEX

MIST Design Criteria & MotivationMIST Design Criteria & Motivation--Low cost (current dropsondes cost >$700), Low cost (current dropsondes cost >$700), the current the current sonde sonde cost is ~$270cost is ~$270

--Small (credit card size)Small (credit card size)

--Lightweight (Lightweight (Gondola to carry 50 sondesGondola to carry 50 sondes))

-- Sensors:Sensors:1. GPS Winds & Altitude1. GPS Winds & Altitude2. Temperature (2. Temperature (thermistorthermistor))3. 3. OEM Humidity sensorOEM Humidity sensor

--Pressure derived from GPS & hydrostaticPressure derived from GPS & hydrostaticequation (launch pressure)equation (launch pressure)

-- Operate at Operate at --7070ºº C (Battery issues and otherC (Battery issues and otherengineering challenges)engineering challenges)

Standard DropsondeStandard Dropsonde

MISTMISTSondeSonde

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Miniature In-situ Sounding Technology (MIST Sonde)

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Goals• Demonstration test of the driftsonde and new miniature

dropsonde concepts for future campaigns

• Explore dynamics of the easterly waves over Africa in support of AMMA-France and the hurricane genesis environments for THORPEX

• Examine the observed vs. operational model evolution ofthese environments for:

– wave structure, CAPEs, CINs, vertical shear, evolution ofmoisture variations associated with Saharan Air Layer moving across the Atlantic, sensitivity of model and observed convection to environmental conditions

• Participate in forecast impact studies

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Trajectory for gondola #8 shown on nextslide.

SciScience Aspect #1: Stratospheric ence Aspect #1: Stratospheric Dynamics (avec Albert Dynamics (avec Albert HeHertzogrtzog))

The balloon trajectoriesThe balloon trajectories,, in the next two slides, show evidence of in the next two slides, show evidence of wavewave--like structures in the lower stratosphere with the intensity like structures in the lower stratosphere with the intensity increasingincreasing during the experimentduring the experiment

A very preliminary indicate that theseA very preliminary indicate that these wavewave--like featureslike features are too are too weak or nonweak or non--existent in the analysis used to initialize some existent in the analysis used to initialize some modelsmodels

We areWe are beginning to explorebeginning to explore the mechanism for these waves the mechanism for these waves (e.g., GARP ghost balloons and (e.g., GARP ghost balloons and Hertzog Hertzog GRL papers) with GRL papers) with preliminarpreliminary hypothesis that the waves are y hypothesis that the waves are mixedmixed--Rossby Rossby gravity gravity waves (easterly waves) at ~20 km as observed over the Pacificwaves (easterly waves) at ~20 km as observed over the Pacific

Does the weakened state in the analysis and forecast have any Does the weakened state in the analysis and forecast have any impact on the troposphere and onimpact on the troposphere and on thethe structure of the easterly structure of the easterly waves and hurricane genesis environment?waves and hurricane genesis environment?

Driftsonde Deployment(eight missions up to 18 day duration)

North American Region

Predicted from Previous Years“Perhaps Life is Always More Complicated (And Hopefully More Interesting) Than Predictions”

Preliminary lookPreliminary look sshowed no howed no westerlieswesterlies

iin several models at this timen several models at this time

ScienceScience Aspects #2: Dry Aspects #2: Dry Intrusions (avec Remy Intrusions (avec Remy RocaRoca))

Dry intrusions from the upperDry intrusions from the upper--troposphere of troposphere of middle latitudes and the Saharan middle latitudes and the Saharan airmass airmass make for a complex and variable humidity make for a complex and variable humidity structurestructure

Dry intrusions from higher latitudes can be Dry intrusions from higher latitudes can be mistaken for the Saharanmistaken for the Saharan air massair mass

Some evidence for Some evidence for tropopause tropopause folding folding reaching the Saharan boundary layerreaching the Saharan boundary layer

Driftsonde dataDriftsonde dataDriftsondeDriftsonde 4: 4: overover extraextra--tropicaltropical dry intrusions dry intrusions andand SaharanSaharan airair

Driftsonde #3Driftsonde #4Driftsonde #5

Driftsonde dataDriftsonde dataDriftsondeDriftsonde 4: 4: overover extraextra--tropicaltropical dry intrusions dry intrusions andand SaharanSaharan airair

Rémy Roca’s dry intrusion diagnostics from NCEP analyses

Vertical profiles of relative humidity fromdriftsonde #4 (passing over extra-tropical dry intrusions), driftsonde #3 (in the vicinity oftropical storm Florence) and driftsonde #5 (in the vicinity of Dakar) between September8th 0600 UTC and 9th 1200 UTC

Driftsonde #3Driftsonde #4Driftsonde #5

SciScience Aspects #3: Easterly Waves aence Aspects #3: Easterly Waves and nd Hurricane GenesisHurricane Genesis

Sampled a relatively unknown environment over the central AtlantSampled a relatively unknown environment over the central Atlantic. ic. Soundings made in both Hurricane Florence and Gordon near time Soundings made in both Hurricane Florence and Gordon near time of intensification when these systems went from a numbered of intensification when these systems went from a numbered depression to a named tropical storm!!depression to a named tropical storm!!

–– Very unstable Very unstable with extremely with extremely moist soundings in lower troposphere (~4 km) moist soundings in lower troposphere (~4 km) with relativewith relatively ly light winds (e.g., light winds (e.g., thermodynamics look similar to environment thermodynamics look similar to environment with slow moving lines for GATE, a.k.a. Barnes, with slow moving lines for GATE, a.k.a. Barnes, LeMone LeMone and othersand others))

Soundings madeSoundings made near thenear the environmentenvironment ofof Hurricane HeleneHurricane Helene while it while it was a named storm but did not catwas a named storm but did not catch this storm ch this storm ((““ChasingChasing HeleneHelene””))

Soundings inSoundings in thethe vicinity of easterly waves over Africavicinity of easterly waves over Africa

–– Still mostly sorting out the data set and determining which waveStill mostly sorting out the data set and determining which waves were s were sampled and which waves become tropical cyclonessampled and which waves become tropical cyclones

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Science Apects #4: Convection, the diurnal cycle and easterly waves over Africa ---Data set example, repeated deployments in

trough of an active easterly wave over Africa from driftsonde mission #1

Driftsonde dataDriftsonde dataDriftsonde Driftsonde 3 in 3 in the vicinity the vicinity of tropical cyclone Florenceof tropical cyclone Florence

Tropical cyclone Florence

Sondes released from driftsonde #3

Deepening Moist Layer

African PBL

Disturbed Environment Near Florence

African Easterly Jet

Increasing Surface Winds

Disturbed Environment Near Florence

Driftsonde Driftsonde datadataDriftsonde Driftsonde 4 in 4 in the vicinity the vicinity of tropical cyclone Gordonof tropical cyclone Gordon

Sondes released from driftsonde #4

Tropical cyclone Gordon

0

2000

4000

6000

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10000

12000

14000

16000

18000

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-100 -50 0 50 100Temperature and Rh

He

igh

t

TemperatureRH

Driftsonde Demonstration• 6 successful missions from the 8 driftsondes launched

– One gondola failure due to electrical discharge from a squall line system that overtook the driftsonde during ascent

– One balloon failure

• Mission length 6 to 18 days (time to cross African and the tropical Atlantic)

• Success for the NCAR driftsonde in terms of a proof of concept including communication, data transmission, sonde launch on demand, long-duration flights, and air traffic approvals

• Success for the new CNES 12 m super-pressure balloons and ballooning system including venting system to counteract loss of ballast when sondes are launched

Dropsonde Demonstration• On average, each gondola carried 34 sonde of the 50 possible (less

due to funding)

• Quality controlled soundings available ~1 Jan 2007 under guidelines of the AMMA data policy (T, rh and winds as a function of height)

• General success: weight down to ~5 ozs, cost lower, and the temperature, humidity, and wind sensors worked well

• However, some clear improvements are required.

– The ability to derive an accurate pressure profile from the hydrostatic equation was limited, which caused us to not send data over the GTS in real-time for the first several gondolas. Investigations continue but the problem was most likely due to inaccuracies in the GPS height of the gondola (esp over Africa) and international security issues (detected by us and resolved by the manufacturer too lateto upgrade the sonde GPS sensors for this mission)

– Sondes will be upgraded for future missions (options are an extremely small and inexpensive wind vs height sonde or a full pressure, temperature, wind and humidity MIST sonde with a cost and weight similar to the current version)

– Reduce failure mode for soundings

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