scholarly journals Avaliação do modelo regional climático para a previsão de temperatura no centro de lançamento de Alcântara

2021 ◽  
Vol 3 (5) ◽  
pp. 2908-2921
Author(s):  
Alexandre Santos De Souza ◽  
Cleber Souza Correa ◽  
Inácio Malmonge Martin

Este estudo avaliou a previsão intrasazonal da temperatura à superfície (2 m de altura) na região do Centro de Lançamento de Alcântara (CLA) utilizando O Regional Climate Model RegCM4.7 em comparação aos dados de reanálises obtidos do modelo de reanalises globalERA5 do European Centre for Medium-Range Weather Forecasts (ECMWF) para os meses de abril de 2019 (estação chuvosa) e outubro de 2019 (estação seca). Foram realizadas 4 (quatro) membros de simulações de temperatura utilizando o RegCM4.7 em horários sinóticos, os quais foram comparadas com os dados observacionais e de reanálises do ERA5. Os resultados indicaram uma boa previsibilidade para a temperatura média nos dois períodos, diferenças inferiores a 1 °C, com um grau de diferença para abril e praticamente coincidindo em outubro. Para as temperaturas máximas médias o RegCM4.7 superestimou em 2 °C para abril e 4 °C para outubro. Para as temperaturas médias mínimas subestimou em 2 °C tanto para abril como para outubro. Essas avaliações indicaram um bom desempenho geral para a previsão de temperaturas médias, contudo, sabendo-se da tendência de superestimar temperaturas máximas médias e subestimar temperaturas mínimas médias, ainda assim, com as devidas correções, poderá ser utilizado com eficácia para a previsão intrasazonal de temperatura à superfície em apoio ao planejamento de operações de lançamento no CLA.   This study evaluated the intraseasonal surface temperature (2 m height) forecast in the Alcântara Launch Center (ALC) region using the Regional Climate Model RegCM4.7 against reanalysis data obtained from the European Center for Medium-Range Weather global Forecasts (ECMWF) reanalysis model ERA5 for the months of April 2019 (rainy season) and October 2019 (dry season). Four members of temperature simulations were performed using RegCM4.7 at synoptic times, which were compared with observational and reanalysis data from ERA5. The results indicated a good predictability for the average temperature in the two periods, differences below 1 °C, with one degree of difference for April and practically coinciding in October. For average maximum temperatures RegCM4.7 overestimated by 2 °C for April and 4 °C for October. For average minimum temperatures, it was underestimated by 2 °C for both April and October. These evaluations indicated a good overall performance for predicting average temperatures, however, knowing the tendency to overestimate average maximum temperatures and underestimate average minimum temperatures, even so, with the appropriate corrections, it can be used effectively for forecasting intraseasonal surface temperature analysis in support of ALC launch operations planning.  

2013 ◽  
Vol 7 (2) ◽  
pp. 615-630 ◽  
Author(s):  
M. Tedesco ◽  
X. Fettweis ◽  
T. Mote ◽  
J. Wahr ◽  
P. Alexander ◽  
...  

Abstract. A combined analysis of remote sensing observations, regional climate model (RCM) outputs and reanalysis data over the Greenland ice sheet provides evidence that multiple records were set during summer 2012. Melt extent was the largest in the satellite era (extending up to ∼97% of the ice sheet) and melting lasted up to ∼2 months longer than the 1979–2011 mean. Model results indicate that near surface temperature was ∼3 standard deviations (σ) above the 1958–2011 mean, while surface mass balance (SMB) was ∼3σ below the mean and runoff was 3.9σ above the mean over the same period. Albedo, exposure of bare ice and surface mass balance also set new records, as did the total mass balance with summer and annual mass changes of, respectively, −627 Gt and −574 Gt, 2σ below the 2003–2012 mean. We identify persistent anticyclonic conditions over Greenland associated with anomalies in the North Atlantic Oscillation (NAO), changes in surface conditions (e.g., albedo, surface temperature) and preconditioning of surface properties from recent extreme melting as major driving mechanisms for the 2012 records. Less positive if not increasingly negative SMB will likely occur should these characteristics persist.


2021 ◽  
Author(s):  
Carolyne Pickler ◽  
Thomas Mölg

<p>Downscaling has been widely used in studies of regional and/or local climate as it yields greater spatial resolution than general circulation models (GCM) can provide.  It can approached in two distinct ways: 1) Statistical and 2) Dynamical.  Statistical downscaling utilizes mathematical relationships between large-scale and regional/local climate to transform GCM or reanalysis data to a higher spatial resolution.  Dynamical downscaling comprises forcing the lateral boundaries of a regional climate model with reanalysis or GCM data.  However, there is no set technique to select said GCM(s).</p><p>A comprehensive yet easily applicable selection procedure was created to address this.  Using reanalysis data and/or observational data, the space-time climatic anomalies and the mean state of the climate are evaluated for the region of interest.  East Africa was utilized as a case study and GISS-E2-H r6i1p3 was found to perform the strongest.  This procedure cannot, however, tell whether the models can reproduce the key processes of the region.  To examine this, the ability of the models to simulate the Indian Ocean Dipole were evaluated.  It was found that higher ranked models were better able to capture it than lower ranked ones.  Furthermore, to ensure that a higher ranked model yielded a better downscaling simulation, three 10-year regional climate model simulations over East Africa were undertaken, where they were respectively forced by the highest ranked GCM (GISS-E2-H r6i1p3), the lowest ranked GCM (IPSL-CM5A-LR r4i1p1) and the MERRA-2 reanalysis product.  The simulated surface temperature and precipitation for Equatorial East Africa were compared with a gridded observational dataset (CRU TS 4.04).  Results showed that the higher ranked GCM produced a better downscaled simulation than the lower ranked one, a result that was more evident for surface temperature than precipitation.</p>


2021 ◽  
Author(s):  
Simon C. Scherrer ◽  
Christoph Spirig ◽  
Martin Hirschi ◽  
Felix Maurer ◽  
Sven Kotlarski

<p>The Alpine region has recently experienced several dry summers with negative impacts on the economy, society and ecology. Here, soil water, evapotranspiration and meteorological data from several observational and model-based data sources is used to assess events, trends and drivers of summer drought in Switzerland in the period 1981‒2020. 2003 and 2018 are identified as the driest summers followed by somewhat weaker drought conditions in 2020, 2015 and 2011. We find clear evidence for an increasing summer drying in Switzerland. The observed climatic water balance (-39.2 mm/decade) and 0-1 m soil water from reanalysis (ERA5-Land: -4.7 mm/decade; ERA5: -7.2 mm/decade) show a clear tendency towards summer drying with decreasing trends in most months. Increasing evapotranspiration (potential evapotranspiration: +21.0 mm/decade; ERA5-Land actual evapotranspiration: +15.1 mm/decade) is identified as important driver which scales excellently (+4 to +7%/K) with the observed strong warming of about 2°C. An insignificant decrease in precipitation further enhanced the tendency towards drier conditions. Most simulations of the EURO-CORDEX regional climate model ensemble underestimate the changes in summer drying. They underestimate both, the observed recent summer warming and the small decrease in precipitation. The changes in temperature and precipitation are negatively correlated, i.e. simulations with stronger warming tend to show (weak) decreases in precipitation. However, most simulations and the reanalysis overestimate the correlation between temperature and precipitation and the precipitation-temperature scaling on the interannual time scale. Our results emphasize that the analysis of the regional summer drought evolution and its drivers remains challenging especially with regional climate model data but considerable uncertainties also exist in reanalysis data sets.</p>


2020 ◽  
Author(s):  
Hussain Alsarraf

<p>The purpose of this study is to examine the impact of climate change on the changes on summer surface temperatures between present (2000-2010) and future (2050-2060) over the Arabian Peninsula and Kuwait. In this study, the influence of climate change in the Arabian Peninsula and especially in Kuwait was investigated by high resolution (36, 12, and 4 km grid spacing) dynamic downscaling from the Community Climate System Model CCSM4 using the WRF Weather Research and Forecasting model. The downscaling results were first validated by comparing National Centers for Environmental Prediction NCEP model outputs with the observational data. The global climate change dynamic downscaling model was run using WRF regional climate model simulations (2000-2010) and future projections (2050-2060). The influence of climate change in the Arabian Peninsula can be projected from the differences between the two period’s model simulations. The regional model simulations of the average maximum surface temperature in summertime predicted an increase from 1◦C to 3 ◦C over the summertime in Kuwait by midcentury.</p><p><strong> </strong></p>


2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Klaus Dethloff ◽  
Ksenia Glushak ◽  
Annette Rinke ◽  
Dörthe Handorf

The regional climate model HIRHAM has been applied to Antarctica driven at the lateral and lower boundaries by European Reanalysis data ERA-40 for the period 1958–1998. Simulations over 4 decades, carried out with a horizontal resolution of 50 km, deliver a realistic simulation of the Antarctic atmospheric circulation, synoptic-scale pressure systems, and the spatial distribution of precipitation minus sublimation (P-E) structures. The simulated P-E pattern is in qualitative agreement with glaciological estimates. The estimated (P-E) trends demonstrate surfacemass accumulation increase at the West Antarctic coasts and reductions in parts of East Antarctica. The influence of the Antarctic Oscillation (AAO) on the near-surface climate and the surface mass accumulation over Antarctica have been investigated on the basis of ERA-40 data and HIRHAM simulations. It is shown that the regional accumulation changes are largely driven by changes in the transient activity around the Antarctic coasts due to the varying AAO phases. During positive AAO, more transient pressure systems travelling towards the continent, and Western Antarctica and parts of South-Eastern Antarctica gain more precipitation and mass. Over central Antarctica the prevailing anticyclone causes a strengthening of polar desertification connected with a reduced surface mass balance in the northern part of East Antarctica.


2021 ◽  
Vol 945 (1) ◽  
pp. 012022
Author(s):  
Chin Kah Seng ◽  
Tan Kok Weng ◽  
Akihiko Nakayama

Abstract Climate change is one of the challenging global issues that our world is facing and it is intensely debated on the international agenda. It is a fact that climate change has brought about many disastrous events on a global scale which affect our livelihoods. Climate models are commonly used by researchers to study the magnitude of the changing climate and to simulate future climate projections. Most climate models are developed based on various interactions among the Earth’s climate components such as the land surface, oceans, atmosphere and sea-ice. In this study, the second-generation Canadian Earth System Model (CanESM2) was statistically downscaled to develop a regional climate model (RCM) based on three representative concentration pathways (RCPs): RCP2.6, RCP4.5 and RCP8.5. The RCM will be used to simulate the average minimum and maximum temperatures and average precipitation for Ipoh, Subang and KLIA Sepang in Peninsular Malaysia for the years 2006 to 2100. The simulated data were bias corrected using the historical observation data of monthly average minimum and maximum temperatures and monthly average rainfall retrieved from the Malaysian Meteorological Department (MMD). The different trends of the simulated data for all the three locations based on the RCP2.6, RCP4.5 and RCP8.5 were evaluated for future climate projection.


Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 924 ◽  
Author(s):  
Liliana Rusu ◽  
Alina Raileanu ◽  
Florin Onea

The aim of the present work is to assess the wind and wave climate in the Black Sea while considering various data sources. A special attention is given to the areas with higher navigation traffic. Thus, the results are analyzed for the sites located close to the main harbors and also along the major trading routes. The wind conditions were evaluated considering two different data sets, the reanalysis data provided by NCEP-CFSR (U.S. National Centers for Environmental Prediction-Climate Forecast System Reanalysis) and the hindcast results given by a Regional Climate Model (RCM) that were retrieved from EURO-CORDEX (European Domain-Coordinated Regional Climate Downscaling Experiment). For the waves, there were considered the results coming from simulations with the SWAN (Simulating Wave Nearshore) model, forced with the above-mentioned two different wind fields. Based on these results, it can be mentioned that the offshore sites seem to show the best correlation between the two datasets for both wind and waves. As regards the nearshore sites, there is a good agreement between the average values of the wind data that are provided by the different datasets, except for the points located in the southern part of the Black Sea. The same trends noticed for the average values remain also valid for the extreme values. Finally, it can be concluded that the results obtained in this study are useful for the evaluation of the wind and wave climate in the Black Sea. Also, they give a more comprehensive picture on how well the wind field provided by the Regional Climate Model, and the wave model forced with this wind, can represent the features of a complex marine environment as the Black Sea is.


2013 ◽  
Vol 52 (7) ◽  
pp. 1576-1591 ◽  
Author(s):  
Jiali Wang ◽  
Veerabhadra R. Kotamarthi

AbstractDynamic downscaling with regional-scale climate models is used widely for increasing the spatial resolution of global-scale climate model projections. One uncertainty in generating these projections is the choice of boundary forcing applied. In this study the Nested Regional Climate Model (NRCM) is used with a grid spacing of 12 km over the United States (excluding Hawaii) to dynamically downscale 2.5° National Centers for Environmental Prediction–U.S. Department of Energy Reanalysis-2 data, with different applications of spectral nudging (SN) for the boundary conditions. Nine numerical experiments for July 2005—each with different wavenumbers and nudging duration periods, applied to different model layers—evaluated the performance of SN in downscaling near-surface fields. The calculations were compared with the North America Regional Reanalysis dataset over four subregions of the contiguous 48 states. Results show significant differences with different wavenumbers, nudging duration periods, and nudging altitudes. The short-period SN with three waves, applied above 850 hPa, showed the highest skill in simulating precipitation, whereas whole-period SN produced a higher skill level and performed slightly better than short-period SN for surface temperature and 10-m wind, respectively. Differences in the performance of SN applied at different altitudes were not significant. On the basis of the comparisons for precipitation, surface temperature, and wind fields over entire contiguous states, whole-period nudging with six waves starting above 850 hPa for downscaling calculations for climate-related variables is recommended. This method improved the performance of the NRCM in predicting near-surface fields by more than 30.5% relative to a case with no nudging.


Sign in / Sign up

Export Citation Format

Share Document