ref: d. fahey, adapted from ipcc 4th assessment, summary for policymakers, feb. 2, 2007
DESCRIPTION
WHAT ARE THE MAJOR HUMAN & NATURAL ACTIVITIES FORCING CLIMATE CHANGE IN THE INDUSTRIAL ERA (1750-2005)?. Ref: D. Fahey, adapted from IPCC 4th Assessment, Summary for Policymakers, Feb. 2, 2007. - PowerPoint PPT PresentationTRANSCRIPT
Ref: D. Fahey, adapted from IPCC 4th Assessment, Summary for Policymakers, Feb. 2, 2007
WHAT ARE THE MAJOR HUMAN & NATURAL ACTIVITIES FORCING CLIMATE CHANGE IN THE INDUSTRIAL ERA (1750-2005)?
1.6 W m-2 x 5.1 x 1014 m2 = 8.16 x 1014 W = 816 TW (about 52 times current global energy consumption)!
RON PRINN, MIT-FEN LUNCHEON TALK, 10/14/08
Global Cycles of Greenhouse Gases are studied using Measurements & Global Circulation models28-level 1.8ox1.8o Model for
Atmospheric Transport & Chemistry (MATCH) uses NCEP meteorology
AGAGE measures 45 gases 20-36 times per day at globally distributed
stations dating back to 1978
How well do we understand Greenhouse
Gas (GHG) Cycles?
AGAGE NETWORK STATIONS
Hateruma (Japan)Mt. Cimone (Italy)
Jungfraujoch (Switzerland) Ny-Alesund (Norway)
AGAGE INSTRUMENTATION1. Medusa GC-MS
2. GC-Multi-detector3. Calibration
1.
3. 2.
MONTREAL PROTOCOL GASES & THEIR REPLACEMENTS
Radiative Forcing from Carbon Dioxide and other Greenhouse gases
CO2
CH4
N2OCFCs
others
TRENDS IN METHANE: WHY DO THEY VARY INTERANNUALLY AND WHY HAVE THEY
DECELERATED IN RECENT YEARS?
QUASI-STEADY STATE: Emissions(CH4) ~ k[OH].Content(CH4) ?Ref: IPCC 4th Assessment, Summary for Policymakers, Feb. 2, 2007
AGAGENOAA
• High-Frequency (13: AGAGE, NOAA, etc.) and Flask (41 comprehensive & 32 more intermittent: NOAA, CSIRO, etc.) monthly mean observations between 1996-2001
• Interannually varying transport (NOAA/NCEP) used in 3D MATCH model (T62, 1.8o x1.8o, 28 levels, 1000-2.9mb) to create the CH4 response of each site to monthly pulses from individual regional processes (sensitivity H(t) matrix)
• Kalman Filter used to solve for: (a) 7 Seasonally-varying processes as monthly varying fluxes (b) 2 Pseudo-steady processes as constant fluxes using annually repeating time/space varying MATCH model OH tuned to AGAGE CH3CCl3 observations
METHANE INVERSE STUDIES USING 3D MATCH MODEL (Chen & Prinn, 2005, 2006)
El Nino winds
La Nina winds
AGAGE observations versus MATCH model at Samoa
MIRROR PLOT
MIRROR PLOT
MATCH Simulates Effects of ENSO Transport on CH4
Ref: Chen & Prinn, J.G.R., 2005
SUMMARY: AVERAGE SEASONAL CYCLES (SELECTED AND ALL DATA SETS)
CAPTURES EXPECTED SEASONAL CYCLES (RICE PEAKS EARLIER)
ReferenceHigh Freq.AllBest
Ref: Chen & Prinn, J.G.R., 2006
Summary: Interannual variability (Monthly Anomalies) 32-33 Tg yr-1 Total Emission increase in 1998 with8-17 Tg yr-1 due to Rice regions Northern/Tropical Wetland and Rice Region Emissions dominate the total variability
Fluxes in Tg yr-1 Northern Wetlands
Tropical Wetlands
Inversion 5-10 8.3-9.9Bottom-up* 12 13
BUT Boreal Fires in Siberia may have also contributed to our deducedstrong Northern wetlands increase
*wetland model driven by 1998 record temperature and large precipitation anomalies (Dlugokencky et al. (2001))
1998 wetland Flux Anomalies
Summary: 5-year averages
_ (literature)
(1) ENERGY RELATED EMISSIONS SMALLER (RUSSIAN GAS LEAKS?)
COMPARED TO PREVIOUS ESTIMATES:
(2) RICE RELATED EMISSIONS LARGER (PROXIMAL WETLANDS OR TROPICAL ECOSYSTEMS?)
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METHANE IS RISING
AGAIN, BUT WHY?
(TRENDS AT AGAGE & CSIRO STATIONS)(Rigby et al, 2008)
RESULTS FOR
EMISSION ANOMALIES
FROM INVERSIONS
(Rigby et al, 2008)
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The hydroxyl free radical (OH) is the major oxidizing chemical in the global atmosphere
It annually removes about 3.7 billion metric tons of trace gases (CO, CH4, higher hydrocarbons, hydro-halocarbons, NOx, SOx, etc.) from the atmosphere..Are the levels of this dominant cleansing chemical changing? A decrease is dangerous!With a lifetime of only about 1 second it is possible to measure locally, but not possible to measure directly at regional to global scales.Use AGAGE measurements of the industrial chemical CH3CCl3, whose major sink is OH, to indirectly estimate large scale OH variations.
[OH
] (10
5 rad
ical
s cm
-3)
Ref: Update of Prinn, Huang et al, G.R.L., 2005
The inferred OH minima generally coincide with strong El Nino’s and/or massive global wildfires (updated from Prinn, Huang, et al, G.R.L.,2005). The 2006-2007 drop is therefore unexpected.
Global weighted average OH inferred from AGAGE CH3CCl3
12.335(U) / 12.835(G)Experimental Atmospheric Chemistry (Fall
2008)Logistics:
Lectures: Tuesdays (usually), 12:30-2:30pm, Room 54-1510Lab Periods: Thursdays (usually), 12:30-2:30pm, Room 54-1811
4 Field Trips: Sun: 9/7, Fri: 10/10, Sat: 11/1, Sat: 11/15Attendance at lectures, labs and especially field trips is mandatory.
Instructors:Ronald G. Prinn, 54-1312, [email protected]
Laura Meredith, 54-1320, [email protected] Potter, 54-1414, [email protected]
Grading: 10% - Participation
20% - Topic 1 - CO2 & Climate20% - Topic 2 - CFCs & Ozone Layer
20% - Topic 3 - Air Pollution & Health30% - Topic 4 - Tropospheric Photochemistry - [20% - Lab Report, 10% - Presentation]
Each student will focus on a chosen aspect of tropospheric photochemistry for their topic 4 lab report and presentation.
A list of possible subjects will be provided mid-semester and student selections are due on Nov. 17th.
Credit: 2-2-8 Undergraduate or Graduate Credits
Stellar website: http://stellar.mit.edu/S/course/12/fa08/12.335/