Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Parameterization

Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection... Two 9-yr runs of the NCAR Community Climate Model version 3 (CCM3) are compared in their simulations of the North American summer monsoon. In a control simulation, the Zhang–McFarlane deep convection scheme is used. For an experimental simulation, the following modifications to the scheme are implemented. The closure is based on the large-scale forcing of virtual temperature, and a relative humidity threshold on convective parcels lifted from the boundary layer is applied. The sensitivity to these modifications for simulating the North American monsoon is investigated. Model validation relies on hourly precipitation rates from surface gauges over the United States, hourly precipitation rates derived from the combination of microwave and radar measurements from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite over Mexico, and CAPE values as calculated from temperature, specific humidity, and pressure fields from the NCEP–NCAR reanalysis. Results show that the experimental run improves the timing of the monsoon onset and peak in the regions of core monsoon influence considered here, though it increases a negative bias in the peak monsoon intensity in one region of northern Mexico. Sensitivity of the diurnal cycle of precipitation to modifications in the convective scheme is highly geographically dependent. Using a combination of gauge-based rainfall rates and reanalysis-based CAPE, it is found that improvements in the simulated diurnal cycle are confined to a convective regime in which the diurnal evolution of precipitation is observed to lag that of CAPE. For another regime, in which CAPE is observed to be approximately in phase with precipitation, model phase biases increase nearly everywhere. Some of the increased phase biases in the latter regime are primarily because of application of the relative humidity threshold. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Climate American Meteorological Society

Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Parameterization

Collier, J. Craig; Zhang, Guang J.
Journal of Climate , Volume 19 (12) – Mar 11, 2005
Download PDF
16 pages

Loading next page...
 
/lp/american-meteorological-society/simulation-of-the-north-american-monsoon-by-the-ncar-ccm3-and-its-wsI3OZLK5E
Publisher
American Meteorological Society
Copyright
Copyright © 2005 American Meteorological Society
ISSN
1520-0442
DOI
10.1175/JCLI3732.1
Publisher site
See Article on Publisher Site

Abstract

Two 9-yr runs of the NCAR Community Climate Model version 3 (CCM3) are compared in their simulations of the North American summer monsoon. In a control simulation, the Zhang–McFarlane deep convection scheme is used. For an experimental simulation, the following modifications to the scheme are implemented. The closure is based on the large-scale forcing of virtual temperature, and a relative humidity threshold on convective parcels lifted from the boundary layer is applied. The sensitivity to these modifications for simulating the North American monsoon is investigated. Model validation relies on hourly precipitation rates from surface gauges over the United States, hourly precipitation rates derived from the combination of microwave and radar measurements from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite over Mexico, and CAPE values as calculated from temperature, specific humidity, and pressure fields from the NCEP–NCAR reanalysis. Results show that the experimental run improves the timing of the monsoon onset and peak in the regions of core monsoon influence considered here, though it increases a negative bias in the peak monsoon intensity in one region of northern Mexico. Sensitivity of the diurnal cycle of precipitation to modifications in the convective scheme is highly geographically dependent. Using a combination of gauge-based rainfall rates and reanalysis-based CAPE, it is found that improvements in the simulated diurnal cycle are confined to a convective regime in which the diurnal evolution of precipitation is observed to lag that of CAPE. For another regime, in which CAPE is observed to be approximately in phase with precipitation, model phase biases increase nearly everywhere. Some of the increased phase biases in the latter regime are primarily because of application of the relative humidity threshold.

Journal

Journal of Climate – American Meteorological Society

Published: Mar 11, 2005

References

  • The North American monsoon.
    Adams
  • The Statistical Analysis of Time Series.
    Anderson
  • The lower atmosphere over the Gulf of California.
    Badan-Dangon
  • Monte Carlo climate forecasting.
    Barnett
  • The simulation of the diurnal cycle of convective precipitation over land in a global model.
    Bechtold
  • Multiscale diagnosis of the North American monsoon system using a variable resolution GCM.
    Berbery
  • Evaluation of the diurnal cycle of precipitation, surface thermodynamics, and surface fluxes in the ECMWF model using LBA data.
    Betts
  • Study of diurnal cycle of convective precipitation over Amazonia using a single column model.
    Betts
  • Surface energy and water balance for the Arkansas–Red River basin from the ECMWF reanalysis.
    Betts
  • Basin-scale surface water and energy budgets for the Mississippi from the ECMWF reanalysis.
    Betts
  • The low-level circulation of the North American monsoon as revealed by QuickSCAT.
    Bordoni
  • The diurnal cycle of tropical precipitation in Tropical Rainfall Measuring Mission (TRMM) satellite and ocean buoy rain gauge data.
    Bowman
  • The role of stability and moisture in the diurnal cycle of convection over land.
    Chaboureau
  • Comparison of precipitation observed over the continental United States to that simulated by a climate model.
    Chen
  • Diurnal cycle of tropical precipitation in a general circulation model.
    Collier
  • A comparison of tropical precipitation simulated by the NCAR Community Climate Model CCM3 with that observed by the Tropical Rainfall Measuring Mission (TRMM) satellite.
    Collier
  • The diurnal cycle and its depiction in the Community Climate System Model.
    Dai
  • Observed and model-simulated diurnal cycles of precipitation over the contiguous United States.
    Dai
  • Sensitivity of the modeled North American monsoon regional climate to convective parameterization.
    Gochis
  • Hydrometeorological response of the modeled North American monsoon to convective parameterization.
    Gochis
  • Modelling the diurnal cycle of deep precipitating convection over land with cloud-resolving models and single-column models.
    Guichard
  • Surges of maritime tropical air northward over the Gulf of California.
    Hales