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Improving Convective Sensitivity to Tropospheric Relative Humidity. Richard Neale (NCAR) and Brian Mapes (RSMAS, University of Miami). AMWG Meeting, Mar 20, 2006. Free Troposphere. Altitude. PBL. 0 Moisture sensitivity +. Undilute. Dilute. Entraining Plume -Cloud water (1 g/kg)
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Improving Convective Sensitivity to Tropospheric Relative Humidity Richard Neale (NCAR) and Brian Mapes (RSMAS, University of Miami) AMWG Meeting, Mar 20, 2006
Free Troposphere Altitude PBL 0 Moisture sensitivity + Undilute Dilute Entraining Plume -Cloud water (1 g/kg) -Freezing below 273K -Entrainment chosen Pseudoadiabatic Ascent -No cloud water -No freezing -No entrainment (but implied) 0.2 X 100% + 0.8 X RHclr = 1.0 X 10% => RHclr = -12.5%
Dilute Undilute JJA FV 2x2.5 1979-1988 Dilute minus GPCP Undilute - GPCP Dilute Undilute
Undilute minus ERS Dilute minus ERS
Dilute Undilute
CAPT CCCP-ARM ParametrizationTestbed Dilute Undilute
Dilute Variance of 5-day ave rainfall Undilute
Dilute ENSO Warm minus Cold DJF Prect. Undilute
Amplitude of Diurnal Cycle (mm/day) (JJA 1984) CAM3 (T85) 3B42 TRMM TMI/PR
Local Time of Daily Rainfall Max CAM3 (T85) 3B42 TRMM TMI/PR
Overall JJA significant improvements (DJF some improvements Africa/Australia rainfall) -Reduction in S. Indian Ocean ITCZ -Enhanced Asian-Monsoon rainfall -Reduced twin ITCZ bias -Improved tropospheric humidity, MSE structure -Decrease in large Pacific high PSL error -Reduction in amplitude of diurnal cycle of rainfall/increased night-time rainfall -More realistic balance of convective/stratiform rainfall -CAPT tests, < half the error through day 5 forecast -ENSO wider Pacific equatorial signal (tentative) -Enhanced subseasonal variability (too much?) Some deterioration -Indian monsoon precipitation excess -South Atlantic circulation pattern -No change or slightly earlier diurnal cycle rainfall maximum