nasa’s modern era retrospective-analysis for research and ... · nasa’s modern era...

NASANASA’’s Modern Era Retrospectives Modern Era Retrospective--analysis analysis for Research and Applications: for Research and Applications:

ValidationValidationGlobal Modeling and Assimilation OfficeGlobal Modeling and Assimilation Office

►►Overview and StatusOverview and Status►►Some early resultsSome early results►►MonitoringMonitoring

Presented by Michael Bosilovich, MERRA Short Course, AMS Annual Meeting, Phoenix AZ, January 11, 2009

NASANASA’’s Modern Era Retrospectives Modern Era Retrospective--analysis for analysis for Research and Applications (MERRA)Research and Applications (MERRA)

►► RetrospectiveRetrospective--analyses use a fixed Global Atmospheric analyses use a fixed Global Atmospheric Model and Data Assimilation System to analyze the Model and Data Assimilation System to analyze the historical satellite and conventional data records into a historical satellite and conventional data records into a continuous global gridded data set including a multitude continuous global gridded data set including a multitude of ancillary weather and climate diagnosticsof ancillary weather and climate diagnostics

►► MERRA uses the latest release of the GMAO Global Earth MERRA uses the latest release of the GMAO Global Earth Observing System Data Assimilation System (GEOSObserving System Data Assimilation System (GEOS--5) 5) and will analyze the period from 1979 and will analyze the period from 1979 –– present, present, assimilating satellite radiances and conventional assimilating satellite radiances and conventional observationsobservations

►► A NASA contribution to CCSP Synthesis and Assessment A NASA contribution to CCSP Synthesis and Assessment Product 1.3: ReProduct 1.3: Re--analyses of historical climate data for analyses of historical climate data for key atmospheric features. Implications for attribution of key atmospheric features. Implications for attribution of causes of observed change.causes of observed change.

3

Years inStream

MERRA 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08Stream 1 10Stream 2 10Stream 3 9ROSB 21G5-AMIP 26EOS

NovNOAA-18

EOS AquaOct

F08

F15

SSM/IJul Dec

F10Nov

DecF11

Dec

DecF13

MayF14

May

Dec Aug

Apr Jul

Apr Jun

Jul

GOES-08

GOES-10

GOES-12

TIROS-NDec Feb

Jul Apr OctNovNOAA-6

FebSep NOAA-7

May Jun Jul OctNOAA-8

Jan NovNOAA-9

NOAA-10Dec Sep

Nov Jan Sep Sep NOAA-11

JunSep NOAA-12

Satellite Radiance Data Streams

JanNOAA-14

SepNOAA-15NovNOAA-16

JulNOAA-17

Dec

TOVS

ATOVS

EOS Aqua

GOESSounders

MERRA will analyze radiances from these satellites, and also several satellite retrieved data products as well as conventional observations (e.g. sondes)

The Changing Observing SystemThe Changing Observing System

1973 – 77K Obs every 6hrs

1979 – 325K Obs every 6hrs

1987 – 550K Obs every 6hrs

2006 – 4.2M Obs every 6hrs

NASANASA’’s Modern Era Retrospectives Modern Era Retrospective--analysis for analysis for Research and Applications (MERRA)Research and Applications (MERRA)

►► Objective: To improve the water cycle representation Objective: To improve the water cycle representation in reanalyses, and support NASA Earth science and in reanalyses, and support NASA Earth science and application activitiesapplication activities

►► 19791979--present (continuing as it is feasible)present (continuing as it is feasible)►► ½½°° horizontal resolution (horizontal resolution (7272 model levels, model levels, sfcsfc--stratstrat))►► 1 hourly1 hourly surface and 2D diagnostic datasurface and 2D diagnostic data►► 6 hourly 36 hourly 3--Dimensional atmospheric analysisDimensional atmospheric analysis►► >150 >150 TbsTbs online storage, many portalsonline storage, many portals►► Production Began May 2008 (complete FallProduction Began May 2008 (complete Fall--2009)2009)►► Home Home -- http://http://gmao.gsfc.nasa.gov/merragmao.gsfc.nasa.gov/merra//►► Data Data -- http://http://disc.sci.gsfc.nasa.govdisc.sci.gsfc.nasa.gov/MDISC//MDISC/►► Discussion Discussion -- http://merrahttp://merra--reanalysis.blogspot.comreanalysis.blogspot.com//

MERRA Production StatusMERRA Production Status

►► This figure is updated regularly at: This figure is updated regularly at: http://gmao.gsfc.nasa.gov/research/merra/progresshttp://gmao.gsfc.nasa.gov/research/merra/progress--events.phpevents.php

Nearly 17 years complete and

shipped to DISC

MERRA ValidationMERRA Validation

►►Experiment Review, Nov 2007Experiment Review, Nov 2007►►Included Short Experiments at native Included Short Experiments at native

resolution (9 months was the longest)resolution (9 months was the longest)Long experiment with coarse resolution (Scout)Long experiment with coarse resolution (Scout)

►►Radiation, clouds, precipitation, surface Radiation, clouds, precipitation, surface temperature, UTH, general circulationtemperature, UTH, general circulation

►►Data sources: SRB, CERES, MODIS, GPCP Data sources: SRB, CERES, MODIS, GPCP existing reanalysesexisting reanalyses

►►Increments (e.g. PIncrements (e.g. P--E), Indian MonsoonE), Indian Monsoon

See also S. Schubert presentation provided in the Docs folder of the flash drive

← Will go over this or something like it

Effect of Water Vapor AnalysisEffect of Water Vapor Analysis

Taylor diagrams for tropical precipitation. GPCP merged precipitation is the reference data set. The diagrams compare spatial correlation (to GPCP) of the analysis to standard deviation normalized by the reference data set. If a field exactly duplicated GPCP, it would be at the 1,1 point. Linear distance to the 1,1 point is a measure of skill in reproducing the reference data set (annual 1979-2005).

MERRA MERRA PrecipPrecip Taylor DiagramsTaylor Diagrams

►► See also: Bosilovich et al (2008, JAMC)See also: Bosilovich et al (2008, JAMC)

General Circulation: Tropical MoistureGeneral Circulation: Tropical Moisture

ERA 40 JRA25

BasinBasin--scale Precipitationscale Precipitation

►► CPC US CPC US ¼¼ gridded gauge datagridded gauge data►► Daily, Jan 1 Daily, Jan 1 –– Sep 30 2004Sep 30 2004►► Consider all of the Mississippi River Basin domainConsider all of the Mississippi River Basin domain►► Comparison with CEOP MultiComparison with CEOP Multi--Models in Poster sessionModels in Poster session

GEOS5

0-6Z 6-12Z 12-18Z 18-0Z

GEOS5GEOS5

JRAJRA

NCEP R1NCEP R1

NCEP R2NCEP R2

EC-OPSEC-OPS

TRMMTRMM

Diurnal Cycle of PrecipitationDiurnal Cycle of Precipitation

JJA v-wind at 850mb (9-yrs)

Mean

Std

MERRA NARR

14.44.114.44.6NCEP2 - CERES

11.5-0.911.4-0.5NCEP1 - CERES

10.315.89.016.2JRA25 - CERES

6.87.67.38.9ECOPS - CERES

12.82.59.15.4MERRA - CERES

2.5-0.72.4-0.8CERES Terra -Aqua

STDAveSTDAve

Jul, 2004Jan, 2004TOA LW difference

(W/m2)

•All reanalyses get similar patterns as observation.•The difference between observations can be a reference for the uncertainty in reanalyses.•For all reanalyses, strongest error happens over tropical convective regions.•MERRA TOA LW flux bias mean and standard deviation are moderate among reanalyses.

TOA LW comparison

of reanalyses

TOA LW TOA LW comparison comparison

of of reanalysesreanalyses

From Junye Chen

•LW-SW Joint Frequency Distribution (JFD) shows the relationship of LW and SW under different atmospheric states.•The shape and location of MERRA LW-SW JFD is closer to CERES observation, while the MERRA pattern is a little stretched.

•From Junye Chen

TOA LWTOA LW--SW Joint Freq. DistributionSW Joint Freq. Distribution

Trends in the Water and Energy CyclesTrends in the Water and Energy Cycles

►► Global P trend mostly Global P trend mostly over Ocean, and over Ocean, and corresponds to corresponds to QvQvIncrementsIncrements

►► AtmAtm Latent heating Latent heating variations antivariations anti--correlated correlated to heating incrementsto heating increments

Precipitation

2.00

2.20

2.40

2.60

2.80

3.00

3.20

1979

1980

1981

1982

1983

1989

1990

1991

1992

1993

1998

1999

2000

2001

mm

day

-1 GlobalLandOcean

Water Vapor Increments

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

1979

1980

1981

1982

1983

1989

1990

1991

1992

1993

1998

1999

2000

2001

mm

day

-1 GlobalLandOcean

Global Heating Rates (W m-2)

60.0

65.0

70.0

75.0

80.0

85.0

1979

1980

1981

1982

1983

1989

1990

1991

1992

1993

1998

1999

2000

2001

MST

0.0

5.0

10.0

15.0

20.0

25.0

AN

A MoistProcessesAnalysis

Net Surface and TOA ImbalanceNet Surface and TOA Imbalance

►► Global surface net imbalance is improving in time, Global surface net imbalance is improving in time, mostly changing over Oceanmostly changing over Ocean

►► The Ocean net imbalance is decreasing in The Ocean net imbalance is decreasing in incoming SW radiation and increasing LEincoming SW radiation and increasing LE

Ocean Sfc Anomalies (W m-2)

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

1979

1980

1981

1982

1983

1989

1990

1991

1992

1993

1998

1999

2000

2001

LEHsSWdnLWdn

Net Heating Sfc and TOA

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1979

1980

1981

1982

1983

1989

1990

1991

1992

1993

1998

1999

2000

2001

W m

-2 SfcTOASFC LTOA LSFC OTOA O

►► Complete budgets Complete budgets are available are available including all including all tendencies and tendencies and analysis incrementsanalysis increments

►► Water (all phases), Water (all phases), Ozone, KE, Enthalpy, Ozone, KE, Enthalpy, IncludedIncluded

►► Also, landAlso, land--only only budgetsbudgets

►► Tremendous effort Tremendous effort by Max Suarez, by Max Suarez, Larry Larry TakacsTakacs and and Randy Randy KosterKoster

Vertically-Integrated Water Vapor Budget for July 1991Vertically-Integrated Water Vapor Budget for July 1991

ANAtqvqvPE

tqv

∂∂

+⋅∇−−=∂∂

Presidents Day Snow Feb 19, 1979Presidents Day Snow Feb 19, 1979

►►Much fewer observations early in the Much fewer observations early in the record, still weather can be reasonablerecord, still weather can be reasonable

GOES IR 17:30Z19FEB1979

(Barbs every other grid space)

Presidents Day Snow Feb 19, 1979Presidents Day Snow Feb 19, 1979

Routine for this animation at \Source\Feb1979

Andrew Aug 24, 1992Andrew Aug 24, 1992

►► All from GDS; Scripts on disc at /Source/AndrewAll from GDS; Scripts on disc at /Source/Andrew

Andrew Aug 24, 1992Andrew Aug 24, 1992

►►Contaminated ERS1 data is usedContaminated ERS1 data is used►►Resolution still too coarse for small Resolution still too coarse for small TCsTCs

Scout SBUV Assimilation Statistics, Mar 1992

Ozone response to questionable data Ozone response to questionable data Increments OzoneIncrements Ozone

Flawed sounding: Flawed sounding: AzoresAzores

►►19791979--1980: A 1980: A persistent sounding persistent sounding west of Portugal is west of Portugal is very different from very different from others nearbyothers nearby

►►The result is a The result is a persistent counterpersistent counter--increment that affects increment that affects energeticsenergetics and and moisture budgets moisture budgets

MERRA Hourly Basin AverageMERRA Hourly Basin Average

Major “Black Frost” episode

MERRA MERRA OnOn--Line Line

AtlasAtlas►► Updated regularly Updated regularly

with monthly with monthly comparisons versus comparisons versus existing reanalyses existing reanalyses and some global and some global observed data setsobserved data sets

►► More comparisons More comparisons being added and will being added and will be redone at the be redone at the completion of MERRAcompletion of MERRA

►► Comments WelcomeComments Welcome

http://gmao.gsfc.nasa.gov/research/merra/prequel/view.php

Example figures from the AtlasExample figures from the Atlas500mb Eddy Height vs JRA25

Precipitation Taylor Diagram, All Reanalyses using GPCP as the reference

MERRA DocumentationMERRA Documentation

►►GEOS5 Model and Assimilation Document, GEOS5 Model and Assimilation Document, Rienecker et al.Rienecker et al.

►►MERRA File Specification, Suarez et al. MERRA File Specification, Suarez et al. (Outlines the output data format, and (Outlines the output data format, and information on variables)information on variables)

►►MERRA Validation, Bosilovich et al. (Results MERRA Validation, Bosilovich et al. (Results of the GEOS5 Validation Experiments, prior of the GEOS5 Validation Experiments, prior to beginning MERRA production)to beginning MERRA production)