AN OVERVIEW OF MERRA: VALIDATION AND ......AN OVERVIEW OF MERRA: VALIDATION AND CHALLENGES FOR...
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AN OVERVIEW OF MERRA: VALIDATION AND CHALLENGES FOR FUTURE REANALYSES CHALLENGES FOR FUTURE REANALYSES Presented by Michael Bosilovich with contributions from many in the GMAO
Transcript of AN OVERVIEW OF MERRA: VALIDATION AND ......AN OVERVIEW OF MERRA: VALIDATION AND CHALLENGES FOR...
AN OVERVIEW OF MERRA: VALIDATION AND CHALLENGES FOR FUTURE REANALYSESCHALLENGES FOR FUTURE REANALYSES
Presented by Michael Bosilovich
with contributions from many in the GMAOy
NASA’S MODERN ERA RETROSPECTIVE-ANALYSIS FOR RESEARCH AND APPLICATIONS (MERRA)
2002 Proposed Objective: Improving the water and energy cycle representation in a reanalysis
GEOS5 system development including NASA global climate model with NCEP GSI data assimilation
Nov 2007 – External User Review Group endorses the Validation Review of GEOS5 for MERRA
Production began in May 2008 Production began in May 2008
Provisional release of 9 yrs data in Dec 20089 yrs. data in Dec 2008
Began realtime pro-duction in Apr 2010
Currently 1979 through May ‘10 are available
NASA’S MODERN ERA RETROSPECTIVE-ANALYSIS FOR RESEARCH AND APPLICATIONS (MERRA)
1979-present (continuing as it is feasible)
½° horizontal resolution (72 model levels, sfc-strat)
1 hourly surface and 2D diagnostic datay g Including complete budgets and extensive meteorology,
lowest model level states
6 hourly 3-Dimensional atmospheric analysis
3 hourly 3-D model background including diagnostics, 3 hourly 3 D model background including diagnostics, coarse resolution
>70 Tbs online storage, many portals (incl. subsetter) g , y p ( )up to realtime processing > 31 years of data
CHALLENGE AND ADVANTAGE OF REANALYSIS
1973 – 77K Obs every 6hrs 1987 – 550K Obs every 6hrs
1979 – 325K Obs every 6hrs 2006 – 4.2M Obs every 6hrs
ASSESSING PRECIPITATION SKILL
Taylor Diagram of Global Annual precipitation skill ofprecipitation skill of existing reanalyses e.g. Bosilovich et al (2008)
PRECIPITATION ANOMALIESPRECIPITATION ANOMALIES
http://gmao.gsfc.nasa.gov/ref/merra/atlas/
Calculating Budgets
ANAtqvqvPE
tqv
g
Complete budgets are available including all t d i dtendencies and analysis increments
Water (all phases), O KEOzone, KE, Enthalpy, Included
Also, land-onlybudgetsbudgets
Tremendous effort by Max Suarez, Larry Takacs andLarry Takacs and Randy Koster
Ocean Precipitation ( mm day-1)Gl b l i i i
WATER AND ENERGY CYCLES TIME SERIESGlobal Ocean
3.6
3.8
4.0
4.2
4.4Ocean Precipitation ( mm day )
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1
Global Precipitation
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2.9
mm
day
-1
Land Precipitation ( mm day-1)
2.4
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GPCP CMAP MERRA JRA Interim NCEPR2
2.3
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GPCP CMAP MERRA JRA Interim NCEPR2
Land
2.62.83.03.23.4
p ( y )
Global P trend mostly over Ocean
Land
1.61.82.02.22.4
over Ocean Land, taken together,
are comparable with 1.4
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GPCP CMAP MERRA JRA Interim NCEPR2
little apparent trend
GLOBAL WATER BALANCEGLOBAL WATER BALANCE
FwPEwvw
Nov98 NOAA15 Jul99 QSCAT
tt
ANA
0 42 9Global P, E, Qvinc (mm day-1)
Jul99 QSCAT Jan01 NOAA16 Aug02 NOAA170.1
0.20.30.4
2.62.72.82.9
g Oct02 AIRS Nov05 NOAA18
0 3-0.2-0.10.0
2 22.32.42.5
-0.4-0.3
2.12.2
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P E Qvinc
NET SURFACE AND TOA IMBALANCENET SURFACE AND TOA IMBALANCE
6.0Ocean Surface Flux Anomalies (W m-2)
0.02.04.0
-6 0-4.0-2.0
-8.0-6.0
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Global surface net imbalance is improving in time, mostly changing over Ocean
LE (87.7) Hs (11.7) SWdn (195.8) LWdn (342.7)
changing over Ocean The Ocean net imbalance is decreasing in incoming SW
radiation and increasing LE
SPATIAL EFFECT OF AMSU (ESTIMATED) ON MERRASPATIAL EFFECT OF AMSU (ESTIMATED) ON MERRA
Increment Change (mm day‐1)Precipitation Change (mm day‐1) Increment Change (mm day 1) 2000‐08 minus 1990‐97
Precipitation Change (mm day 1) 2000‐08 minus 1990‐97
Increases in SH midlatitude and Indian OceanSPCZ i i l l d i SPCZ increase is also related to moist convergence
African decrease needed more attention
Many analyses can help understanding/validation/development Many analyses can help understanding/validation/development 2003-2004 LH Flux Difference from a Remotely Sensed estimate
(Vinukollu et al 2010)
CORRECTING THE TIME SERIESCORRECTING THE TIME SERIES
Increment Change (mm day‐1)2000‐08 minus 1990‐97
Analysis increments contain the information Analysis increments contain the information to remove trend artifacts induced by step function changes in observing system input.Robertson et al (2010) From Robertson et al (2010)
BASIN-SCALE PRECIPITATIONBASIN SCALE PRECIPITATION
GEOS5
CPC US ¼ gridded gauge dataDail Jan 1 2003 Dec 31 2004
mm day-1
MERRA Daily, Jan 1 2003 – Dec 31 2004 Area average over the Mississippi River Basin domain
TROPOPAUSE FOLD
TROPOPAUSE FOLD
KATRINA AT LANDFALLKATRINA AT LANDFALL
mm hr-1
ANDREW AUG 24, 1992
ANDREW AUG 24, 1992
ERS observations overlayy MERRA Obs (including O-F and O-A) to be
available for user access soon
BEGINNING RESEARCH
MERRA Precipitation shows skill compared to GPCP, relative to other reanalysesreanalyses
Trends are on the order of other reanalyses, but the bias is much improved
Energy balance smallest in the recent Energy balance smallest in the recent period, ~8Wm-2 imbalance
Global P, E (mm day-1)
Remaining issues in reanalyses: model bias appears as trends in conjunction with the changing observing system can affect many
0.20
0.30
0.40
0.50
2.70
2.80
2.90
3.00c observing system, can affect many
aspects of the reanalysis Researchers must evaluate the
processes important to their-0.20
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0.00
0.10
2.30
2.40
2.50
2.60
Qv i
nc
P,E
processes important to their project; Analyzed observations should help
-0.302.20
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P E Qv Incr
THANK YOUTHANK YOU Home - http://gmao.gsfc.nasa.gov/merra/
D t htt //di i f /MDISC/ Data - http://disc.sci.gsfc.nasa.gov/MDISC/ Atlas -
http://gmao.gsfc.nasa.gov/ref/merra/atlas/ Discussion – Discussion
http://merra-reanalysis.blogspot.com/
merra-questions@listserv gsfc nasa gov merra [email protected] [email protected]
850mb specific humidity from Bangui (64650), compared to MERRA grid point, monthly mean anomalies
AMAZON TIME SERIESAMAZON TIME SERIES
10.0Amazon Precipitation (mm day-1)
4 0
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an eb
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Apr ay un Ju
l
ug ep Oct ov ecJ F M A Ma Ju J Au S O No D
MERRA (99-06) MERRA (79-98)GPCP (99-06) GPCP (79-98)
Amazon precipitation generally increases, but th i l h hift i th l lthere is also a phase shift in the annual cycle
More water in the soil, after AMSU assimilation
ATMOSPHERIC HEATINGATMOSPHERIC HEATING
Global Heating Rates (W m-2)
20.0
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85.0
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NA
ST
5 0
10.0
70 0
75.0 AN
MS
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9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8
Moist Processes
Analysis
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