Reliability Assessment of Regional Climate Modeling: Case study in Johor State, Malaysia

This paper presents the work of statistically downscaling the CAN ESM 2 (Canada Earth System Model 2) climate data into regional climate data to produce the future climate scenario using the RCP (Representative Concentration Pathways) 2.6,4.5 and 8.5 green-house gas concentration trajectory suggested by Intergovernmental Panel on Climate Change Fifth Assessment Reports (IPCC-AR5). Selected location for regional climate downscaling includes Batu Pahat (1° 52’ N 102° 59’ E) and Kulai (1° 38’ N 103° 40’ E), downscaled outcome of monthly rainfall (mm), daily maximum (Tmax) and daily minimum (Tmin) temperature (°C) was produced by using SDSM (Statistical Downscaling Model) software to calibrate the CANESM2 output with the historical data. Quantile-mapping bias correction by using exponential distribution function was done to obtain bias corrected rainfall data. Reliability test using Pearson correlation coefficient was done by comparing between actual historical data. Based on Pearson correlation applied on bias corrected results, for Batu Pahat, the most suitable RCP model for both Tmax and Tmin is RCP 2.6, with correlation of 0.74 and 0.72, most suitable model for rainfall is RCP 4.5 with correlation of 0.24. For Kulai, the most suitable RCP model for Tmin is RCP 8.5, with correlation of 0.63, for Tmax and rainfall the suitable model is RCP 2.6, with correlation of 0.73 and 0.36. In overall, the more appropriate model to describe the climate for both Batu Pahat and Kulai based on Pearson correlation from year 2006 to 2019 is RCP 2.6, as the RCP 2.6 model are having higher correlation to the historical data.

Characterization of vegetation fraction estimated using spot-vegetation NDVI data for regional climate modeling in India

lkj & ,e- ,e- 5 tSls eslksLdsy tyok;q fun’kksZa }kjk ouLifr ¼oh- ,Q-½ dh lwpuk nsus dk dk;Z egRoiw.kZ gSA fun’kZu ¼ekWMfyax½ esa lkekU; :Ik ls lcls vf/kd iz;qDr dh xbZ tyok;q laca/kh ekfld oh- ,Q- gSA oh- ,Q- dh lwpuk,¡ ,u- vks- ,- ,- & ,- oh- ,p- vkj- vkj- ,u- Mh- oh- vkbZ- HkweaMyh; vk¡dM+k lsVksa dk mi;ksx djrs gq, xqVesu vkSj bXukVkso ¼1988½ ¼th- vkbZ-½ }kjk rS;kj dh xbZ gSA bl 'kks/k&i= esa Hkkjrh; {ks= ds vizSy 1998 ls uoacj 2003 dh vof/k ds LikWV& ost+hVs’ku 10 fnolh; fefJr ,u- Mh- oh- vkbZ- ds mRiknksa dk mi;ksx djrs gq, 1 fd- eh- ds oh- ,Q- ds vk¡dM+k lsV rS;kj djus ds ckjs esa crk;k x;k gSA LikWV&osthVs’ku ds 0 % vkSj 100 % dh oh- ,Q- ls laca) ,u- Mh- oh- vkbZ- dh laosnd fof’k"V izHkkolhek,¡ th- vkbZ- ds 0-04 vkSj 0-52 dh rqyuk esa Øe’k: 0-04 vkSj 0-804 ikbZ xbZaA th- vkbZ- ds tyok;q laca/kh oh- ,Q ds lkFk izkIr fd, x, oh- ,Q ds vk¡dM+ksa dh rqyuk dh xbZ gSA rhu v{kka’kh; {ks=ksa ¼<16] 16&24] > 24½ ds fy, oh- ,Q- ds fo’ys"k.k ls th- vkbZ- ls 15 % rd dh fHkUurkvksa dk irk pyk gSA o"kkZ&vk/kkfjr Ñf"k okys {ks= esa mYys[kuh; fHkUurk dk irk pyk gSA oh- ,Q- ls izkIr fd, x, ekSleh vkSj o"kZ&izfro"kZ dh fHkUurkvksa ds ifj.kkeksa ij fopkj&foe’kZ fd;k x;k gSA Vegetation fraction (VF) is an important input in mesoscale climate models, such as MM5. The most commonly used VF inputs in modeling is the climatic monthly VF generated by Gutman and Ignatov (1998) (GI) using NOAA-AVHRR NDVI global data sets. This paper reports the generation of 1 km VF data set using SPOT-VEGETATION 10-day composite NDVI products from April 1998 to November 2003 for the Indian region. Sensor-specific thresholds of NDVI associated with 0% and 100% VF for SPOT-VEGETATION were found to be 0.04 and 0.804, respectively, in contrast to 0.04 and 0.52 of GI. Comparison of derived VF with climatic VF of GI was carried out. Analysis of VF for three latitudinal zones (<16, 16-24, >24) indicated the differences up to 15 percent from GI. Significant difference was observed for the area having rain-fed agriculture. Results of the seasonal and year-to-year variations of derived VF are discussed.

West African monsoon precipitation impacted by the South Eastern Atlantic biomass burning aerosol outflow

The West African Monsoon (WAM) is a complex system depending on global climate influences and multiple regional environmental factors. Central and Southern African biomass-burning (SABB) aerosols have been shown to perturb WAM during episodic northward inter-hemispheric transport events, but a possible dynamical connection between the core of the SABB aerosol outflow and the WAM system remains unexplored. Through regional climate modeling experiments, we show that SABB aerosols can indeed impact WAM dynamics via two competitive regional scale and inter-hemispheric dynamical feedbacks originating from (i) enhanced diabatic heating occurring in the Southeastern Atlantic low-cloud deck region, and (ii) aerosol and cloud-induced sea surface temperature cooling. These mechanisms, related to aerosol direct, semi-direct, and indirect effects, are shown to have different seasonal timings, resulting in a reduction of June to September WAM precipitation, while possibly enhancing late-season rainfall in WAM coastal areas.

Changes in the temperature of the Guadalajara metropolitan zone, México under climate change scenarios / Cambios en la temperatura de la zona metropolitana de Guadalajara, México bajo escenarios de cambio climático

In the present study analyzed the average and extreme temperatures observed and simulated by regional models in the Guadalajara Metropolitan Zone (GMZ), Jalisco, Mexico. Data of daily mean, minimum and maximum temperatures of stations in the GMZ during the period 1971-2000 have been used to study the observed changes in the average and extreme temperatures. In addition, an assessment of future scenarios for the average and extreme temperatures associated with the increase in the concentration of greenhouse gases was performed using simulations of a PRECIS regional climate modeling to create the climate for present (1971-2000), and future projections for 2030, 2050 and 2080. Observational analysis of stations suggests warming through increased intensity and frequency of hot events and also with the decrease in the frequency of cold events. More than 35 to 76% of the stations have a tendency to the decrease in the number of cold events and near 39 to 64% of the stations show a growing trend in the hot events. The percentage of stations to global warming through the rates of intensity of the highs maximums, lowest minimum temperatures is 37 to 70% and the 30 to 65% of the stations, respectively. Observational analysis for the GMZ as a whole also shows similar results. Anomalies to the average and extreme temperatures per month during the period of data show an increase (decrease) in the frequency of hot (cold) events for every month. In general, PRECIS simulations under both scenarios A1B and A2 indicate warm events increase and decrease of the cold extreme events towards the end of the 21st century. Both show similar patterns, but the scenario A2 shows slightly lower magnitudes of projected changes. Temperatures are likely to increase in the year, but it is expected that changes in summer to be more prominent.

Evaluating the Performance of Cumulus Convection Parameterization Schemes in Regional Climate Modeling System

In this study, we explored the performance of the cumulus convection parameterization schemes of Regional Climate Modeling System (RegCM) towards the Indian summer monsoon (ISM) of a catastrophic year through various numerical experiments conducted with different convection schemes (Kuo, Grell amd MIT) in RegCM. The model is integrated at 60KM horizontal resolution over Indian region and forced with NCEP/NCAR reanalysis. The simulated temperature at 2m and the wind at 10m are validated against the forced data and the total precipitation is compared with the Global Precipitation Climatology Centre (GPCC) observations. We find that the simulation with MIT convection scheme is close to the GPCC data and NCEP/NCAR reanalysis. Our results with three convection schemes suggest that the RegCM with MIT convection scheme successfully simulated some characteristics of ISM of a catastrophic year and may be further examined with more number of convection schemes to customize which convection scheme is much better.

Modeling the Influence of Upstream Land-atmosphere Coupling on the 2017 Persistent Drought over Northeast China

Persistent drought events that cause serious damages to economy and environment are usually intensified by the feedback between land surface and atmosphere. Therefore, reasonably modeling land-atmosphere coupling is critical for skillful prediction of persistent droughts. However, most high-resolution regional climate modeling focused on the amplification effect of land-atmosphere coupling on local anticyclonic circulation anomaly, while less attention was paid to the non-local influence through altering large-scale atmospheric circulation. Here we investigate how the antecedent land-atmosphere coupling over the area south to Lake Baikal (ASLB) influences the drought events occurred over its downstream region (Northeast China; NEC) by using Weather Research and Forecasting (WRF) model and linear baroclinic model (LBM). When the ASLB is artificially forced to be wet in the WRF simulations during March-May, the surface sensible heating is weakened and results in a cooling anomaly in low level atmosphere during May-July. Consequently, the anticyclonic circulation anomalies over ASLB and NEC are weakened, and the severity of NEC drought during May-July cannot be captured due to the upstream wetting in March-May. In the LBM experiments, idealized atmospheric heating anomaly that mimics the diabatic heating associated with surface wetness is imposed over ASLB, and the quasi-steady response pattern of 500-hPa geopotential height to the upstream wetting is highly consistent with that in the WRF simulation. In addition, the lower level heating instead of the upper level cooling makes a major contribution to the high pressure anomaly over NEC. This study implies the critical role of modeling upstream land-atmosphere coupling in capturing downstream persistent droughts.

Generating long-term high-resolution land-use change datasets for regional climate modeling in CORDEX domains

&lt;p&gt;Land-use and land cover (LULC) are continuously changing due to environmental changes and anthropogenic activities. Many observational and modeling studies show that LULC changes are important drivers altering land surface feedbacks and land-atmosphere exchange processes that have substantial impact on climate on the regional and local scale. Yet, most long-term regional climate modeling studies do not account for these changes. Therefore, within the WCRP CORDEX Flagship Pilot Study LUCAS (Land Use Change Across Scales) a new workflow was developed to generate high-resolution annual land cover change time series based on past reconstructions and future projections. First, the high-resolution global land cover dataset ESA-CCI LC (~300 m resolution) is aggregated and converted to a 0.1&amp;#176; resolution, fractional plant functional type (PFT) dataset. Second, the land use change information from the land-use harmonized dataset (LUH2), provided at 0.25&amp;#176; resolution as input for CMIP6 experiments, is translated into PFT changes employing a newly developed land use translator (LUT). The new LUT was first applied to the EURO-CORDEX domain. The resulting LULC maps for past and future - the LUCAS LUC dataset - can be applied as land use forcing to the next generation RCM simulations for downscaling CMIP6 by the EURO-CORDEX community and in the framework of FPS LUCAS. The dataset includes land cover and land management practices changes important for the regional and local scale such as urbanization and irrigation. The LUCAS LUC workflow is applied to further CORDEX domains, such as Australasia and North America. The resulting past and future land cover changes will be presented, and challenges regarding the application of the new workflow to different regions will be addressed. In addition, issues related to the implementation of the dataset into different RCMs will be discussed.&lt;/p&gt;

Future surface mass balance of the Elbrus Glacial Complex under climate change

&lt;p&gt;The evolution of the Elbrus glacier complex, consisting of two dozen of glaciers, in the last two decades of the 20th century and at the beginning of the 21st century generally corresponded to the trend of a decrease in the glaciated area of &amp;#8203;&amp;#8203;the whole Caucasus. Over the period 1960-2014, the area of &amp;#8203;&amp;#8203;Elbrus glaciation decreased by approximately 15%, and over two decades 1997-2017 - by almost 11%. As of 2017, the area of &amp;#8203;&amp;#8203;Elbrus glaciation was estimated to ca. 112 sq. km, its volume exceeded 5 cub. km. Elbrus glaciation contributes significantly to the formation of the hydrological regime in the region, and, therefore, may be considered as a major challenge ti the regional socio-economic development. The latter circumstance requires an accurate assessment of the glacial runoff, and, consequently, the calculation of the surface mass balance of the glacial complex. We use an energy balance model to calculate the current and future surface mass balance. The series of observations at the Terskol meteorological station, located fifteen kilometers from the southern spurs of Elbrus, and the Mestia meteorological station, located somewhat further, on the territory of Georgia on the southern slope of the Main Caucasian ridge, as well as data from automatic weather stations on Elbrus slopes and on Djankuat glacier a few tens of kilometers from Elbrus, were applied for model forcing to reproduce present surface mass balance. The modeling results were validated by comparison with the measured surfave mass balance components on Garabashi glacier, one of the glaciers on the southern slope of Elbrus. Climate projections until the end of the 21st century for the Elbrus region were composed on the basis of multi-model results of regional climate modeling within the CORDEX project for various scenarios.&lt;/p&gt;&lt;p&gt;We demonstrate that simultaneous surface air temperature and insolation growth accompanied by decrease in precipitation, predicted by multi-model regional climate modeling and downscaled to the Central Caucasus area, will cause essential lifting of the equilibrium line altitude and shrinking of accumulation area. As a result, we must expect an accelerated degradation of Elbrus glaciation in forthcoming decades. &amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;The reported study was funded by RFBR and RS, project number 21-55-100003&lt;/p&gt;