scholarly journals Supplementary material to "Bias correction of multi-ensemble simulations from the HAPPI model intercomparison project"

Author(s):  
Fahad Saeed ◽  
Ingo Bethke ◽  
Stefan Lange ◽  
Ludwig Lierhammer ◽  
Hideo Shiogama ◽  
...  
Author(s):  
Bian He ◽  
Xiaoqi Zhang ◽  
Anmin Duan ◽  
Qing Bao ◽  
Yimin Liu ◽  
...  

AbstractLarge-ensemble simulations of the atmosphere-only time-slice experiments for the Polar Amplification Model Intercomparison Project (PAMIP) were carried out by the model group of the Chinese Academy of Sciences (CAS) Flexible Global Ocean-Atmosphere-Land System (FGOALS-f3-L). Eight groups of experiments forced by different combinations of the sea surface temperature (SST) and sea ice concentration (SIC) for pre-industrial, present-day, and future conditions were performed and published. The time-lag method was used to generate the 100 ensemble members, with each member integrating from 1 April 2000 to 30 June 2001 and the first two months as the spin-up period. The basic model responses of the surface air temperature (SAT) and precipitation were documented. The results indicate that Arctic amplification is mainly caused by Arctic SIC forcing changes. The SAT responses to the Arctic SIC decrease alone show an obvious increase over high latitudes, which is similar to the results from the combined forcing of SST and SIC. However, the change in global precipitation is dominated by the changes in the global SST rather than SIC, partly because tropical precipitation is mainly driven by local SST changes. The uncertainty of the model responses was also investigated through the analysis of the large-ensemble members. The relative roles of SST and SIC, together with their combined influence on Arctic amplification, are also discussed. All of these model datasets will contribute to PAMIP multi-model analysis and improve the understanding of polar amplification.


2018 ◽  
Author(s):  
Fahad Saeed ◽  
Ingo Bethke ◽  
Stefan Lange ◽  
Ludwig Lierhammer ◽  
Hideo Shiogama ◽  
...  

Abstract. Prior to using climate data as input for sectoral impact models, statistical bias correction is commonly applied to correct climate model data for systematic deviations. Different approaches have been adopted for this purpose, however the most common are those based on the transfer functions, generated to map the distribution of the simulated historical data to that of the observations. Here, we present results of a novel bias correction method, developed for Inter-Sectoral Impact Model Intercomparison Project Phase 2b (ISIMIP2b) and applied to outputs of different GCMs generated within the HAPPI (Half A degree Additional warming, Projections, Prognosis and Impacts) project. We have employed various analysis measures including mean seasonal differences, ensemble variability, annual cycles, extreme indices as well as a global hydrological model to assess the performance of ISIMIP2b bias correction technique. The results indicate substantial improvements after the application of bias correction when compared against observational data. Moreover, the extreme indices as well as output of global hydrological model also reveal a marked improvement. At the same time, the ensemble spread of the original data is preserved after the application of bias correction. We find that the bias corrected HAPPI data can provide a reliable basis for sectoral climate impact projections.


2006 ◽  
Vol 7 (4) ◽  
pp. 755-768 ◽  
Author(s):  
Newsha K. Ajami ◽  
Qingyun Duan ◽  
Xiaogang Gao ◽  
Soroosh Sorooshian

Abstract This paper examines several multimodel combination techniques that are used for streamflow forecasting: the simple model average (SMA), the multimodel superensemble (MMSE), modified multimodel superensemble (M3SE), and the weighted average method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multimodel combination results were obtained using uncalibrated DMIP model simulations and were compared against the best-uncalibrated as well as the best-calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the accuracy levels of the multimodel simulations. This study revealed that the multimodel simulations obtained from uncalibrated single-model simulations are generally better than any single-member model simulations, even the best-calibrated single-model simulations. Furthermore, more sophisticated multimodel combination techniques that incorporated bias correction step work better than simple multimodel average simulations or multimodel simulations without bias correction.


2016 ◽  
Author(s):  
Mark J. Webb ◽  
Timothy Andrews ◽  
Alejandro Bodas-Salcedo ◽  
Sandrine Bony ◽  
Christopher S. Bretherton ◽  
...  

2020 ◽  
Author(s):  
Zebedee R. J. Nicholls ◽  
Malte Meinshausen ◽  
Jared Lewis ◽  
Robert Gieseke ◽  
Dietmar Dommenget ◽  
...  

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