Observations for testing model processes

Transcription

1 Observations for testing model processes Does increasing model resolution facilitate a deeper level of model - processes evaluation? Depends on the process but definitely yes for moist physical processes. Graeme Stephens Cal. Institute of Technology, JPL & Uni of Reading Co-chair of GEWEX

2 Outline EO background Two examples of process evaluation GEWEX GC & PROES PRIMAVERA process evaluation focus?

3 We have a wide collection of EOs teaching us much about the Earth system as it operates today.

4 JPL Earth Science Flight Projects Operational ~10km ~10km Formulation/ Development Mission Studies/Concepts Rapdscat (2014) AIRS (2002)) CloudSat (2006) GRACE-FO ACRIMSAT Jason-1 Soil Moisture: SMAP (2017) One (1999) advantage (2001) of high ASCENDS CO (2015) resolution comes with 2 (2020) OCO-2 (2014) MISR GRACE Jason 3* (1999) (2002) (2016) ~10km ~1km ~250m ~500km model resolution matches the intrinsic ~1km TES (2004) ~10km Ocean Surface Topography Mission (JASON-2; 2008) FlightProjects update ~10km use of observational simulators the more the resolution of the obs the less ambiguous are DESDynI GEO-CAPE (TBD) the interpretation of the comparisons ~10km ~100km MLS (2004) ~10km ~10km Sea Surface Salinity: Aquarius ( ) COSMIC-2* (2015+) ECOSTRESS (2017) SWOT (2019) OCO-3 (NLT 2016) Ventures under review ~1km D-Train ~1km StormSat Doppler Radar on ISS HyspIRI Ocean Vector Winds ACE 2025

5 We are also developing data records on finer and finer scales, like 1km

6 And we are producing more integrated data records Arctic Observation and Reanalysis Integrated System: A New Data Product for Validation and Climate Study Matthew W. Christensen 1,2, Ali Behrangi 2, and Graeme L. Stephens 2, Bull Amer Met Soc., 2016 Arctic energy balance CloudSat Profiles in January 2008 (#) P E = 140 ± 8.5 mm/yr 259 ± ± 41 Multiple satellite, surface and reanalysis data sources are matched and gridded Arctic hydrological cycle Ocean Precipita on CloudSat - rain - snow 340 ± GPCP 422 NCEP 278 MERRA 356 ECMWF ± 13 Ocean Evapora on NCEP 233 MERRA 211 ASR 234 Runoff NCEP 157 MERRA 91 GLDAS ± 35 LAND Precipita on CloudSat - rain - snow GPCP 291 CMAP 218 GLDAS 236 GPCC 228 NCEP 256 MERRA 272 ECMWF 277 LAND Evapora on NCEP 147 MERRA 117 ASR 66 OCEAN 62% LAND 38%

7 Processes 1) convection The influence of water vapor on deep convection and convection organization. 50% 25% 90% 70% Bechtold et al, 2008)

8 The convective process ECMWF T df dz = l(f' - F) Cloud-top MSE C p T + gz + L v q * MODIS T b B º g T parcel - T env T env T parcel =193 K; T env =198 K Negatively buoyant!

9 Buoyancy Entrainment rate ΔT = T parcel T env (K) Deep convection: B <0 & λ < 10%/km Can we develop tests of the assumptions about environmental dependences of convection with approaches like this (UTCC PROES - later)? Entrainment Rate (%/km) Terminal cumulus congestus: B < 0 & λ up to 50%/km Transient cumulus congestus: B > 0 & λ ~ 10%/km

10 Process evaluation 2) warm rain GFDL CM3 r crit =6.0mm R eff (top) = 5-10mm MODIS r crit =8.2mm r crit =10.6mm CloudSat Golaz et al (2013) Historical temperature change simulations are sensitive to the details of how warm precipitation is triggered The most realistic warm rain initiation produces the worst simulation. Small changes in reflected energy appear to force a transition into a different regime that appears to be triggered by the Mt Agung eruption in early 1960s.

11 Cryosphere-Climate Interactions Ocean-Atmosphere Interactions Land-Atmosphere Interactions Troposphere-Stratosphere Interactions Grand Challenges Joint Scientific Committee Joint Planning Staff Modeling Advisory Council Data Advisory Council Working Groups on: Couple Modeling (WGCM), Region Climate (WGRC), Seasonal to Interannual Prediction (WGSIP), Numerical Experimentation (WGNE) CliC CLIVAR Decadal Prediction GEWEX SPARC Regional Sea-Level Rise Cryosphere in a Changing Climate Changes in Water Availability Aerosols, Precipitation & Cloud Systems Climate Extremes 11

12 Water Availability GC GEWEX Questions To what degree can we close the water balance today? How will the character of fresh water availability change in the coming decades? Can we be confident in predictions about how the water cycle will change in the future? Q1: How can we better understand and predict precipitation variability and changes? Schewe et al.., 2014, PNAS Q2: How do changes in the land surface and hydrology influence past and future changes in water availability and security? Q3: How does a warming world affect climate extremes, and especially droughts, floods and heat waves, and how do land processes, in particular, contribute? Each degree of warming is projected to decrease renewable water resources by at least 20% for an additional 7% of the global population.

13 Water Availability GC - Themes Precipitation observations? Model performance? Land-water processes models and observations? Models improvements EVALUATE Hydrological sensitivity? Spatial pattern of precip change? ( wet wetter, dry drier?) Regional changes to precipitation intensity (Convection?) Interactions between land water dynamics and atmospheric processes? Modeling human impacts PREDICT UNDERSTAND

14 Physical system cannot be considered in isolation of human activities! Artificial reservoir 7 (Oki and Kanae, Science, 2006) (T. Oki, U. Tokyo) 3 14

15 Putting the human impact into model systems is a glaring need - this need becomes more acute as model resolution increases Solander et al., 2015

16 GEWEX PROES - Process Evaluation Studies underdevelopment This grew out of the obs4mip meeting where participants felt the issue of using obs more intelligently to probe process understanding was needed PROES is begiining to grow into a WCRP cross cut activity Five GEWEX-related PROES activities developing, one led by CliC Upper Tropospheric Clouds & Convection (UTCC, GEWEX and SPARC) lead Stubenrauch and Stephens Ice mass balance (lead Larour, Sophie Nowicki), GEWEX with CLiC Radiative Kernels for Climate (lead Soden) Mid-lat storms (lead Tselioudis, Jakob) Soil moisture climate (lead Sonia Seneviratne) Might we develop a PRIMAVERA-centric PROES? What would the focus be?

17 GEWEX Hydroclimatology Panel Regional hydroclimate projects Globally distributed extensive regional data sets : water and energy cycle observations (in situ and space borne and modeling data) Global Data Centers; data management system / GEO Prototype for Water Cycle Observations Under development is a US RHP its Regional climate and hydrological modeling and process Descriptions scope is being defined now. It will be Hydrological Applications and Forecasting (Drought monitoring, Hydrological composed of multiple projects - one Ensemble Predictions ) dealing with water and the SW. This will be a combination of model and GEWEX REGIONAL HYDROCLIMATE PROJECTS Saskatchewan River Basin (SRB) Mackenzie GEWEX Studies (MAGS) Baltic Baltic Sea Sea Experiment Experiment (BALTEX) (BALTEX) Northern NorthernEurasia EurasiaEarth Earth Science SciencePartnership Partnership (NEESPI) (NEESPI) GEWEX Asia Monsoon Experiments (GAME) North American Water Program (NAWP) Climate Prediction Program for the Americas (CPPA) Large Scale BiosphereAtmosphere Experiment in Amazonia (LBA) Current RHPs Former RHPs Prospective RHPs Monsoon MonsoonAsian AsianHydroHydroAtmosphere AtmosphereScience Science Research Researchand and prediction predictioninitiative Initiative (MAHASRI) (MAHASRI) HYdrological HYdrological cycle cycle in in the the Mediterranean Mediterranean EXperiment EXperiment (HYMEX) (HYMEX) African Monsoon Multidisciplinary Analysis (AMMA) La Plata Basin (LPB) HYVIC HYVIC "Ozewex" "Ozewex" Murray-Darling Basin (MDB) collecting relevant observations. NCAR has produced a CONUS wide hydro-met simulation RHPs Proposed including the 4km BALTEX NAWP scale. HYMEX HYVIC LBA TPE LPB BALTIC-EARTH MAHASRI OZEWEX MDB AMMA New NEESPI SasRB - CCRN