The set up of the RICO intercomparison case Louise Nuijens, A. Pier Siebesma and Margreet van Zanten Photo courtesy Bjorn Stevens KNMI and Wageningen University, The Netherlands

Initial objective to focus one single day: January 11 th 2004 –Almost complete suite of measurement facilities present –Average amount of precip : 0.6 mm/day

However, not the best choice: 1.Atmospheric state variable during the day 2.No way to derive LS-budget for one specific day 3.LES results create too vigorous clouds

Alternative: Construct a composite based on a suppressed period from 16/12/04 till 08/01/05 Average precip in this period: 0.34 mm/day

Average Soundings for this period

To obtain LS forcings: Use a high-res hindcast for the whole RICO period.

Total rainfall rate RACMO

Large Scale Forcings: subsidenceHor. q-advection Hor. T-advection

Radiative Tendency

Surface Conditions

Budget Analysis K/day 0.05 g/kg /day

SCM vs LES profiles

RICO vs BOMEX

Microphysics Flight Nc [cm -3 ]Precipitation [Wm -2 ] RF / /- 0.8 RF / /- 0.4 RF / /- 0.5 RF / /- 0.2 RF / /- 0.8 RF / /- 0.6 Nc of case study set to 45

What is a cloud? (or how to define a cloudy/rainy gridcell?) Set up: q c or N r > 0 (or  ) -> not so useful for bin models We need a physically based threshold! Choices:* threshold based on q c /q r or N c /N r * waterweighted (to calculate mean N) Preferentially one which is suitable for RICO data analysis as well.

DALES sensitivity

sensitivity

DHARMA sensitivity

Threshold Based on q c and q r : 0.01and g/kg Based on N r 5 per liter Photo courtesy Bjorn Stevens