Title: Evaluation of cloud‐resolving and limited area model intercomparison simulations using TWP‐ICE observations: 2. Precipitation microphysics

Abstract

Abstract Ten 3‐D cloud‐resolving model (CRM) simulations and four 3‐D limited area model (LAM) simulations of an intense mesoscale convective system observed on 23–24 January 2006 during the Tropical Warm Pool–International Cloud Experiment (TWP‐ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, colocated UHF and VHF vertical profilers, and a Joss‐Waldvogel disdrometer in an attempt to explain a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One‐moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rainwater contents (RWCs) that are similar to observed. Two‐moment rain schemes with a gamma shape parameter ( μ ) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one‐moment schemes but lower RWCs. Two‐moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and, thus, may have issues balancing raindrop formation, collision‐coalescence, and raindrop breakup. Assuming a μ of 2.5 rather than 0 for the raindrop size distribution improves one‐moment scheme biases, and allowing μmore » to have values greater than 0 may improve excessive size sorting in two‐moment schemes. Underpredicted stratiform rain rates are associated with underpredicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. A limited domain size also prevents a large, well‐developed stratiform region like the one observed from developing in CRMs, although LAMs also fail to produce such a region.« less

Authors:

Varble, Adam ^[1]; Zipser, Edward J. ^[1]; Fridlind, Ann M. ^[2]; Zhu, Ping ^[3]; Ackerman, Andrew S. ^[2]; Chaboureau, Jean‐Pierre ^[4]; Fan, Jiwen ^[5]; Hill, Adrian ^[6]; Shipway, Ben ^[6]; Williams, Christopher ^[7]

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+ Show Author Affiliations

1. Department of Atmospheric Sciences University of Utah Salt Lake City Utah USA
2. NASA Goddard Institute for Space Studies New York New York USA
3. Department of Earth Sciences, Florida International University Miami Florida USA
4. Laboratoire d'Aerologie University of Toulouse/CNRS Toulouse France
5. Department of Climate Physics Pacific Northwest National Laboratory Richland Washington USA
6. Met Office Exeter UK
7. Cooperative Institute for Research in Environmental Science University of Colorado Boulder and the NOAA/Earth System Research Laboratory Boulder Colorado USA

Publication Date:

Thu Dec 18 00:00:00 EST 2014

Sponsoring Org.:

USDOE

OSTI Identifier:

1402124

Grant/Contract Number:  

DEFG0208ER64557

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Name: Journal of Geophysical Research: Atmospheres Journal Volume: 119 Journal Issue: 24; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English