Improving the Simulation of the West African Monsoon Using the MIT Regional Climate Model

نویسندگان

  • Rebecca L. Gianotti
  • Elfatih A. B. Eltahir
  • REBECCA L. GIANOTTI
  • ELFATIH A. B. ELTAHIR
  • Ralph M. Parsons
چکیده

This paper presents an evaluation of the performance of the Massachusetts Institute of Technology (MIT) regional climate model (MRCM) in simulating the West African monsoon. The MRCM is built on the Regional ClimateModel, version 3 (RegCM3), but with several improvements, including coupling of Integrated Biosphere Simulator (IBIS) land surface scheme, a new surface albedo assignment method, new convective cloud and convective rainfall autoconversion schemes, and a modified scheme for simulating boundary layer height and boundary layer clouds. To investigate the impact of these more physically realistic representations when incorporated into MRCM, a series of experiments were carried out implementing two land surface schemes [IBIS with a new albedo assignment, and the Biosphere–Atmosphere Transfer Scheme (BATS)] and two convection schemes (Grell with the Fritsch–Chappell closure, and Emanuel in both the default form and modified with the new convective cloud cover and a rainfall autoconversion scheme). The analysis primarily focuses on comparing the rainfall characteristics, surface energy balance, and large-scale circulations against various observations. This work documents significant sensitivity in simulation of the West African monsoon to the choices of the land surface and convection schemes. Despite several deficiencies, the simulation with the combination of IBIS and themodifiedEmanuel schemewith the new convective cloud cover and a rainfall autoconversion scheme shows the best performance with respect to the spatial distribution of rainfall and the dynamics of the monsoon. The coupling of IBIS leads to representations of the surface energy balance and partitioning that show better agreement with observations compared to BATS. The IBIS simulations also reasonably reproduce the dynamical structures of the West African monsoon circulation.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks

Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exist documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate change, in particular during the mid-Holocene, when climate models consistently underestimate the int...

متن کامل

Evaluation of the performance of the CMIP5 General Circulation Models in predicting the Indian Ocean Monsoon precipitation over south Sistan and Baluchestan, using the past hydrological changes in the region

1-Introduction Climate change refers to any significant change in the existing mean climatic conditions within a certain time period (Jana and Majumder, 2010; Giorgi, 2006). Earth's climate change through history has happened (Nakicenovic et al., 2000; Bytnerowicz et al., 2007). 2-Materials and methods In this study, daily precipitation and daily maximum (Tmax) and daily minimum (Tmin) tempera...

متن کامل

The low-resolution CCSM2 revisited: new adjustments and a present-day control run

The low-resolution (T31) version of the Community Climate System Model CCSM2.0.1 is revisited and adjusted by deepening the Greenland-Scotland ridge, changing oceanic mixing parameters, and applying a regional freshwater flux adjustment at high northern latitudes. The main purpose of these adjustments is to maintain a robust Atlantic meridional overturning circulation which collapses in the ori...

متن کامل

Development and Application of a Mesoscale Climate Model for the Tropics: Influence of SST Anomalies on the West African Monsoon

A mesoscale climate model (MCM) is developed from the Pennsylvania State University/ National Center for Atmospheric Research (PSU/ NCAR) MM5 model to simulate the West African summer monsoon. Results from the MCM are compared to observations, a reanalysis, and GCM output to show that the MCM reasonably simulates the West African monsoon climate and its variability, and improves on many shortco...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2014