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Simulations of the Present and Future Precipitation Climate of the Central
Andes
COAWST Modelling System Training
27 August 2014
Stephen D. Nicholls and Karen I. Mohr
NASA-Goddard Space Flight Center
Precipitation climate: Diurnal cycle, total rainfall, distribution
Motivation: GCMs and CORDEX lack temporal and spatial resolution. Central Andes very sensitive to climate change.
Objectives:Determine stability and feasibility of
COAWST as a regional climate modelRun year-long COAWST simulation to
gain precipitation climate “snapshots”
Definition and objectives
Model Configuration (1)COAWST rev 727 (May
2012)WRF
2 domains (27, 9 km)61 vertical levelsModel top: 50 hPa
ROMS1 domain (~10 km)16 vertical levelsOpen boundaries
No SWANCurrent and future
wave climate?Coupling: WRF 1 <>
ROMS
WRF
ROMS
Model Configuration (2)Lateral boundaries:
Atm, Ocn: MIROC5 (0.7°)Tides: OSU
Time steps:WRF: 60 sec, 20 secROMS: 10 sec
Coupling: 30 minsFree-running simulationModified landuse
USGS = 1991, MODIS = 2003Forest and glacier loss
WRF
ROMS
SimulationsAll simulations for entire year (Oct-Oct)“Current” climate (2003-04)
WRF uncoupled, WRF-ROMS coupledFuture climate (2031-32, 2059-60, 2087-
88)Two parts
RCP comparisons (RCP 4.5, 6.0, 8.5)Year comparisons (RCP 6.0)
Current Climate: Convection
Cumulus parameterization (Kain-Fritsch) off domain 2Over-generation of rain when active
Model and parameterization at 9 km??
Current Climate: Precipitation + SST
TRMM = Tropical Rainfall Measuring Mission Daily 3B42ECM03 = ECMWF interim analysis
WMH03 = WRF with MIROC5 input, no ROMSCMH03 = WRF with MIROC5 input, coupled to ROMS
Current Climate: Precipitation + SST
TRMM = Tropical Rainfall Measuring Mission Daily 3B42ECM03 = ECMWF interim analysis
WMH03 = WRF with MIROC5 input, no ROMSCMH03 = WRF with MIROC5 input, coupled to ROMS
Current Climate: Precipitation + SST
TRMM = Tropical Rainfall Measuring Mission Daily 3B42ECM03 = ECMWF interim analysis
WMH03 = WRF with MIROC5 input, no ROMSCMH03 = WRF with MIROC5 input, coupled to ROMS
Current Climate: Precipitation + SST
TRMM = Tropical Rainfall Measuring Mission Daily 3B42ECM03 = ECMWF interim analysis
WMH03 = WRF with MIROC5 input, no ROMSCMH03 = WRF with MIROC5 input, coupled to ROMS
Current Climate: Precipitation + SST
TRMM = Tropical Rainfall Measuring Mission Daily 3B42ECM03 = ECMWF interim analysis
WMH03 = WRF with MIROC5 input, no ROMSCMH03 = WRF with MIROC5 input, coupled to ROMS
Plots:Top
(Oct)Bottom
(June)
Ocean upwelling
Decreased instability
Atmospheric impacts: θe and Sfc Winds
No change to distribution, but changes in average precip
∆Precip daysCuzco -9Sajama +6Sucre +21Tuni -11
Andes Diurnal Cycle
Future Climate: Precipitation
CMH03 = WRF-ROMS simulation from 2003, with historical MIROC5 input
CMR6031 = WRF-ROMS simulation from 2031, with MIROC5 RCP 6.0 input
CMR6059 = WRF-ROMS simulation from 2059, with MIROC5 RCP 6.0 input
CMR6087 = WRF-ROMS simulation from 2087, with MIROC5 RCP 6.0 input
Future Climate: Precipitation
CMH03 = WRF-ROMS simulation from 2003, with historical MIROC5 input
CMR6031 = WRF-ROMS simulation from 2031, with MIROC5 RCP 6.0 input
CMR6059 = WRF-ROMS simulation from 2059, with MIROC5 RCP 6.0 input
CMR6087 = WRF-ROMS simulation from 2087, with MIROC5 RCP 6.0 input
Future Climate: Precipitation
CMH03 = WRF-ROMS simulation from 2003, with historical MIROC5 input
CMR6031 = WRF-ROMS simulation from 2031, with MIROC5 RCP 6.0 input
CMR6059 = WRF-ROMS simulation from 2059, with MIROC5 RCP 6.0 input
CMR6087 = WRF-ROMS simulation from 2087, with MIROC5 RCP 6.0 input
Future Climate: Precipitation
CMH03 = WRF-ROMS simulation from 2003, with historical MIROC5 input
CMR6031 = WRF-ROMS simulation from 2031, with MIROC5 RCP 6.0 input
CMR6059 = WRF-ROMS simulation from 2059, with MIROC5 RCP 6.0 input
CMR6087 = WRF-ROMS simulation from 2087, with MIROC5 RCP 6.0 input
Future Climate: Precipitation
CMH03 = WRF-ROMS simulation from 2003, with historical MIROC5 input
CMR6031 = WRF-ROMS simulation from 2031, with MIROC5 RCP 6.0 input
CMR6059 = WRF-ROMS simulation from 2059, with MIROC5 RCP 6.0 input
CMR6087 = WRF-ROMS simulation from 2087, with MIROC5 RCP 6.0 input
Diurnal cycle fairly robust
Temp precip “bump” Cuzco,
SajamaUpper air
∆Precip days (2087-2003)Cuzco -12Sajama -9Sucre -16Tuni -20
Future Andes Diurnal Cycle
WRF-ROMS runs lean toward a La Niña patternMIROC issue or ROMS bias or WRF radiation issue
or forcing issueConvective parameterization: No parameterization
works well short term, but less effective long termPotential issues with model configuration?
Eg. WRF model top, etc.Problem with two-way interaction when both WRF
grids not coupled to ROMS.Model buffer zonesFuture work
Remaining questions
Landcover/landuse changeModified raw MODIS
landcover (WPS_geog)Landcover change rates
Amazon (AZ) = ↓7000.0 km2/yr (Davidson et al. 2012) > 2003
Atlantic Forest (AF): ↓0.343%/yr (Ribiero et al. 2009)
Chaco (CH): ↓2.2%/yr (Zak et al. 2004)
Tropical Glaciers (TG): 0.6785% (Slayback and Yegar 2006)
Forest (#1-5 vary) to cropland (#12)
Ice (#25) to tundra (#20)
• Microphysics – Goddard• Longwave Rad. – New Goddard• Shortwave Rad. – New Goddard• Surface layer – Eta similarity• Land Surface – NOAH• Boundary Layer – Mellor-Yamada-Janjic• Cumulus – Kain Fritsch (Turned off domain 2)
WRF Parameterizations
#define ROMS_MODEL# define WRF_MODEL# define MCT_INTERP_OC2AT#define UV_ADV#define UV_COR#define UV_VIS2#define MIX_S_UV#define TS_U3HADVECTION#define TS_C4VADVECTION#undef TS_MPDATA# define UV_LOGDRAG#define DJ_GRADPS#define TS_DIF2#define MIX_GEO_TS#define SALINITY#define SOLVE3D#define SPLINES#undef AVERAGES#define NONLIN_EOS#define MASKING
ROMS Parameterizations#define MCT_LIB# undef BULK_FLUXES# define ATM2OCN_FLUXES# define ANA_SSFLUX# undef LONGWAVE_OUT#undef MY25_MIXING# define KANTHA_CLAYSON# define N2S2_HORAVG#define RADIATION_2D /* ok */#define RAMP_TIDES /* ok */#defineSSH_TIDES /* ok */#define ADD_FSOBC /* ok */#define ANA_FSOBC /* ok */#defineUV_TIDES /* ok */#define ADD_M2OBC /* ok */#define ANA_M2OBC /* ok */#define EAST_FSCHAPMAN #define EAST_M2FLATHER #define EAST_M3RADIATION #define EAST_TRADIATION /*