Effect of lateral boundary scheme on the simulation of tropical cyclone track in regional climate model RegCM3

The dependence of the RegCM3 (Regional Climate Model version 3) downscaling skill on initial conditions (ICs) and lateral boundary conditions (LBCs) are investigated for the 1998 summer flood along the Yangtze River Basin in China. The effect of IC uncertainties is depicted by 15 realizations starting on each consecutive day from April 1 to 15 while all ending on September 1, 1998 with identical driving LBCs, analyses are based on June, July and August simulations. The result reveals certain IC effect on precipitation for daily evolution but little for summer mean geographical distribution. In contrast, the effect of LBCs uncertainties as represented by four different reanalyses are notably larger in both daily evolution and summer mean distribution. The ensemble average among either 15 IC realizations or 4 LBC runs does not show important skill improvement over the individuals. None of the RegCM3 simulations (including the ensemble means) captured the observed main rain band along the Yangtze River Basin. This general failure suggests the need for further model physics improvement.

Download Full-text

Potential use of a regional climate model in seasonal tropical cyclone activity predictions in the western North Pacific

Climate Dynamics ◽

10.1007/s00382-011-1268-x ◽

2011 ◽

Vol 39 (3-4) ◽

pp. 783-794 ◽

Cited By ~ 20

Author(s):

Andie Y. M. Au-Yeung ◽

Johnny C. L. Chan

Keyword(s):

Tropical Cyclone ◽

Regional Climate Model ◽

North Pacific ◽

Western North Pacific ◽

Climate Model ◽

Regional Climate ◽

Tropical Cyclone Activity ◽

Cyclone Activity ◽

Potential Use

Download Full-text

Investigation of the Sensitivity of Water Cycle Components Simulated by the Canadian Regional Climate Model to the Land Surface Parameterization, the Lateral Boundary Data, and the Internal Variability

Journal of Hydrometeorology ◽

10.1175/2008jhm979.1 ◽

2009 ◽

Vol 10 (1) ◽

pp. 3-21 ◽

Cited By ~ 23

Author(s):

Biljana Music ◽

Daniel Caya

Keyword(s):

Regional Climate Model ◽

Land Surface ◽

Water Budget ◽

Climate Model ◽

Initial Conditions ◽

Regional Climate ◽

Internal Variability ◽

Lateral Boundary ◽

Annual Cycles ◽

Lateral Boundary Conditions

Abstract This study investigates the sensitivity of components of the hydrological cycle simulated by the Canadian Regional Climate Model (CRCM) to lateral boundary forcing, the complexity of the land surface scheme (LSS), and the internal variability arising from different models’ initial conditions. This evaluation is a contribution to the estimation of the uncertainty associated to regional climate model (RCM) simulations. The analysis was carried out over the period 1961–99 for three North American watersheds, and it looked at climatological seasonal means, mean (climatological) annual cycles, and interanual variability. The three watersheds—the Mississippi, the St. Lawrence, and the Mackenzie River basins—were selected to cover a large range of climate conditions. An evaluation of simulated water budget components with available observations was also included in the analysis. Results indicated that the response of climatological means and annual cycles of water budget components to land surface parameterizations and lateral boundary conditions varied from basin to basin. Sensitivity to lateral boundary conditions is, in general, smaller than sensitivity to LSS and tends to be stronger for the northern basins (Mackenzie and St. Lawrence). Interannual variability was unaffected by changes in LSS and in driving data. Internal variability triggered by different initial conditions and the nonlinear nature of the climate model did not significantly affect either the 39-yr climatology, the climatological annual cycles, or the interannual variability. A comparison with observations suggests that although the simple Manabe-based LSS may be adequate for simulations of climatological means, skillful simulation of annual cycles require the use of a state-of-the-art LSS.

Download Full-text

Can Bias Correction of Regional Climate Model Lateral Boundary Conditions Improve Low-Frequency Rainfall Variability?

Journal of Climate ◽

10.1175/jcli-d-16-0654.1 ◽

2017 ◽

Vol 30 (24) ◽

pp. 9785-9806 ◽

Cited By ~ 22

Author(s):

Eytan Rocheta ◽

Jason P. Evans ◽

Ashish Sharma

Keyword(s):

Boundary Conditions ◽

Regional Climate Model ◽

Bias Correction ◽

Climate Model ◽

Regional Climate ◽

Low Frequency ◽

Lateral Boundary ◽

Model Simulations ◽

Low Frequency Variability ◽

Climate Model Simulations

Global climate model simulations inherently contain multiple biases that, when used as boundary conditions for regional climate models, have the potential to produce poor downscaled simulations. Removing these biases before downscaling can potentially improve regional climate change impact assessment. In particular, reducing the low-frequency variability biases in atmospheric variables as well as modeled rainfall is important for hydrological impact assessment, predominantly for the improved simulation of floods and droughts. The impact of this bias in the lateral boundary conditions driving the dynamical downscaling has not been explored before. Here the use of three approaches for correcting the lateral boundary biases including mean, variance, and modification of sample moments through the use of a nested bias correction (NBC) method that corrects for low-frequency variability bias is investigated. These corrections are implemented at the 6-hourly time scale on the global climate model simulations to drive a regional climate model over the Australian Coordinated Regional Climate Downscaling Experiment (CORDEX) domain. The results show that the most substantial improvement in low-frequency variability after bias correction is obtained from modifying the mean field, with smaller changes attributed to the variance. Explicitly modifying monthly and annual lag-1 autocorrelations through NBC does not substantially improve low-frequency variability attributes of simulated precipitation in the regional model over a simpler mean bias correction. These results raise questions about the nature of bias correction techniques that are required to successfully gain improvement in regional climate model simulations and show that more complicated techniques do not necessarily lead to more skillful simulation.

Download Full-text

Assessment of the Regional Climate Model Version 3 over the Maritime Continent Using Different Cumulus Parameterization and Land Surface Schemes

Journal of Climate ◽

10.1175/jcli-d-11-00025.1 ◽

2012 ◽

Vol 25 (2) ◽

pp. 638-656 ◽

Cited By ~ 69

Author(s):

Rebecca L. Gianotti ◽

Dongfeng Zhang ◽

Elfatih A. B. Eltahir

Keyword(s):

Boundary Conditions ◽

Regional Climate Model ◽

Land Surface ◽

Climate Model ◽

Regional Climate ◽

Lateral Boundary ◽

Convection Scheme ◽

Maritime Continent ◽

Model Version ◽

Lateral Boundary Conditions

Abstract This paper describes an assessment of the Regional Climate Model, version 3 (RegCM3), coupled to two land surface schemes: the Biosphere–Atmosphere Transfer System, version 1e (BATS1e), and the Integrated Biosphere Simulator (IBIS). The model’s performance in simulating precipitation over the Maritime Continent was evaluated against the 3-hourly Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis 3B42 product. It is found that the model suffers from three major errors in reproducing the observed rainfall histogram: underestimation of the frequency of dry periods, overestimation of the frequency of low-intensity rainfall, and underestimation of the frequency of high-intensity rainfall. Additionally, the model does not accurately reproduce the observed timing of the diurnal rainfall peak, particularly over land. These four errors persisted regardless of the choice of lateral boundary conditions, convective parameterization scheme, or land surface scheme. The magnitude of the wet–dry bias in the simulated volumes of rainfall was, however, strongly dependent on the choice of the convection scheme and lateral boundary conditions. The Grell convection scheme with Fritsch–Chappell closure was the best performing of the convection schemes, having the smallest error magnitudes in both the rainfall histogram and average diurnal cycle, and also having good representation of the land surface energy and evapotranspiration components. The 40-yr ECMWF Re-Analysis (ERA-40) was found to produce better simulations of observed rainfall when used as lateral boundary conditions than did the NCEP–NCAR reanalysis. Discussion of the nature of the major model errors is provided, along with some suggestions for improvement.

Download Full-text