Steven Pawson Data Assimilation Office Global Modeling and Assimilation Office GEOS Meteorological Products June 15, 2003 Evolution, status, plans

Forecast (F) Analysis (A): Meteorology & transport System stats O – A O – F for monitoring Assimilation cycle Observations (O) Constraints (SST, O 3, …) Multi-day forecast INPUTPRODUCTS MODELS GCM (physical) Assimilation (statistical)

Developmental overview of the operational GEOS-DAS MODEL OBSERVATIONS ANALYSIS 4×5L46 2×2.5L46 2×2.5L70 1×1L48 1×1.25L55 GEOS GCM FVCCM NESDIS – Retrieved TOVS Temperature TOVS/AMSU Radiance Sea-Surface Wind from Scatterometer Conventional Observations (radiosondes, aircraft, …) Total Precipitable Water OptimalInterpolation Physical-Space Statistical Analysis System Incremental Analysis Update Intermittent Update GEOS-3 Terra 1999/11 – 2002/10 GEOS-2 TRMM 1997/11 – 1999/12 GEOS-4 FVDAS 2002/10 - present GEOS-1 UARS 1991/ /09 STRAT 1995/ /05 MAESA 1994/ /02

Improved agreement with radiosondes as analysis evolved GEOS-1 GEOS-2 GEOS-3 OI PSAS NESDIS/TOVS T BIAS CORRECTION month T [K] Analyzed Temperature: 100 hPa, 20°S-20°N Improvements at tropical tropopause as analysis evolved Prototype GEOS-4

Major changes in GEOS-4 (aka fvDAS) New GCM: Lin-Rood transport and NCAR CCM3 physics: –Resolved transport superior –Sub-grid transport “different” –Known deficiencies in deep convection scheme “Brutal” data insertion replaces IAU –Can shock the system (precipitation, etc.) Radiance-based use of infrared sounder data (actually late GEOS-3) Resolution: 1.25°×1° with 55 levels to 0.01hPa (with TOVS radiances to 0.4hPa)

ReSTS: Reanalysis for Stratospheric Trace-gas Studies Produce state-of-the-art analyses for May 1991 until April 1995 (eventually until “the present”) Re-examine UARS data in the framework of more accurate meteorological analyses Perform a set of sensitivity studies for selected periods, looking at: –Model formulation (e.g., gravity waves) –Radiative impacts of ozone and Pinatubo aerosol –Use of different data types (e.g., UARS data) Promote closer interactions with chemists, for constituent assimilation

Tropical tropopause region Daily temperatures are in good agreement with sondes, show annual progression with inter-seasonal, intra-seasonal and interannual variability Temperature: 100hPa, 20°S-20°N T [K]

Status/future of ReSTS May 1991 – September 1994 completed at 2.5°×2° with 55 levels –Uses ERA-40 “conventional” observations, TOVS level-1b data, ERS-1 scatterometer, … –Identical configuration to operational GEOS-4, except for lower resolution (& data availability) –TOVS problem in October 1994 – now resolved, & –Skin-temperature problem discovered – now fixed May 1991 – “present” will be done at 1.25°×1°L55 with a couple of extra modifications (late 2003) –Incorporates “MODIS” period (EOS) –Additional GWD –May implement trace gases (ozone, CO, CO 2 )

Recent bug fixes in GEOS-4 Skin-temperature assimilation was found to have a slowly growing feature, propagating from polar regions (affects ReSTS, MODIS reprocessing, operations) - CORRECTED Some cloud-mass-flux fields were not implemented – NOW IMPLEMENTED AND TURNED ON Other minor problems fixed

Global Modeling and Assimilation Office New office, intended to address NASA’s needs in global modeling, for studies of climate and weather, in conjunction with space-based observations Includes and expands the activities of: –Data Assimilation Office (DAO) –NASA’s Seasonal to Interannual Prediction Project (NSIPP) Effective June 15, 2003

Modeling (Atmosphere, Ocean, Land) Max Suarez Meteorological Assimilation (Weather in climate) Ron Gelaro Sub-Seasonal to Decadal Variability (weeks to seasons to years) Siegfried Schubert Trace Constituents (Ozone, Carbon Species, Aerosols, Transport, …) Steven Pawson Instrument team liaisonMan-Li Wu GMAO: Michele Rienecker, head

Evolution: GSFC Earth Sciences DAONSIPP “Weather” Seasonal to Interannual GISS Climate GMAO Global Modeling and Assimilation Office Atmosphere, Land and Ocean (including coupling) on all timescales Focus on the combination of (innovative) space-based observations with modeling Assimilation and Modeling on all timescales

Cloud Mass Flux: Sensitivities Cloud-base mass flux (kg/m2/s) for JJA from two GCM runs, identical apart from the strength of rain re-evaporation in the RAS convection scheme. Global mean precipitation differs by only 5% between the two runs, but substantial sensitivity is evident in these plots. Both “weak” and “strong” values are within observational bounds Bacmeister, Suarez & Kistler (2003)

Looking ahead to GEOS-5 Comprehensive testing with various physics parameterizations (e.g., Relaxed Arakawa- Schubert convection, PBL, radiation code) New grid-point analysis technique replacing PSAS (efficient for large numbers of observations from new sensors) Emphasis on modeling and assimilation Resolution: 2.5°×2° (“low”) through 0.625°×0.5° (“standard assimilation”) and higher Possibilities: geodetic grid, non-hydrostatic core Consultation with chemistry modeling and assimilation groups … support for “online” and “offline” capabilities

Online and offline chemistry OnlineOffline Accurate transportMissing high-frequency transients Sub-grid transport implicitly included Sub-grid transport needs special effort PLUS data volumes Every user must run the GCM GCM not needed Data volume versus computational demands/accuracy This should be a discussion topic for tomorrow