scholarly journals Responses of Energy Budget and Evapotranspiration to Climate Change in Eastern Siberia

10.5772/14161 ◽  
2011 ◽  
Author(s):  
Hotaek Park ◽  
Takeshi Yamazaki ◽  
Takeshi Oht
2021 ◽  
Vol 65 (3) ◽  
pp. 335-352
Author(s):  
Boris K. Biskaborn ◽  
Biljana Narancic ◽  
Kathleen R. Stoof-Leichsenring ◽  
Lyudmila A. Pestryakova ◽  
Peter G. Appleby ◽  
...  

AbstractIndustrialization in the Northern Hemisphere has led to warming and pollution of natural ecosystems. We used paleolimnological methods to explore whether recent climate change and/or pollution had affected a very remote lake ecosystem, i.e. one without nearby direct human influence. We compared sediment samples that date from before and after the onset of industrialization in the mid-nineteenth century, from four short cores taken at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko, eastern Siberia. We analyzed diatom assemblage changes, including diversity estimates, in all four cores and geochemical changes (mercury, nitrogen, organic carbon) from one core taken at an intermediate water depth. Chronologies for two cores were established using 210Pb and 137Cs. Sedimentation rates were 0.018 and 0.033 cm year−1 at the shallow- and deep-water sites, respectively. We discovered an increase in light planktonic diatoms (Cyclotella) and a decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites, related to more recent warmer air temperatures and shorter periods of lake-ice cover, which led to pronounced thermal stratification. Diatom beta diversity in shallow-water communities changed significantly because of the development of new habitats associated with macrophyte growth. Mercury concentrations increased by a factor of 1.6 since the mid-nineteenth century as a result of atmospheric fallout. Recent increases in the chrysophyte Mallomonas in all cores suggested an acidification trend. We conclude that even remote boreal lakes are susceptible to the effects of climate change and human-induced pollution.


2019 ◽  
Vol 44 (12) ◽  
pp. 810-817 ◽  
Author(s):  
O. A. Anisimov ◽  
E. L. Zhil’tsova ◽  
K. O. Shapovalova ◽  
A. A. Ershova

2018 ◽  
Vol 10 (12) ◽  
pp. 4589 ◽  
Author(s):  
Lei Tian ◽  
Jiming Jin ◽  
Pute Wu ◽  
Guo-yue Niu

Climatic elasticity is a crucial metric to assess the hydrological influence of climate change. Based on the Budyko equation, this study performed an analytical derivation of the climatic elasticity of evapotranspiration (ET). With this derived elasticity, it is possible to quantitatively separate the impacts of precipitation, air temperature, net radiation, relative humidity, and wind speed on ET in a watershed. This method was applied in the Wuding River Watershed (WRW), located in the center of the Yellow River Watershed of China. The estimated rate of change in ET caused by climatic variables is −10.69 mm/decade, which is close to the rate of change in ET (−8.06 mm/decade) derived from observable data. The accurate estimation with the elasticity method demonstrates its reliability. Our analysis shows that ET in the WRW had a significant downward trend, but the ET ratio in the WRW has increased continually over the past 52 years. Decreasing precipitation is the first-order cause for the reduction of ET, and decreasing net radiation is the secondary cause. Weakening wind speed also contributed to this reduction. In contrast, regional warming led to an increase in ET that partly offset the negative contributions from other climatic variables. Moreover, reforestation can affect the energy budget of a watershed by decreasing albedo, compensating for the negative influence of global dimming. The integrated effect from precipitation and temperature can affect the energy budget of a watershed by causing a large fluctuation in winter albedo.


2019 ◽  
Author(s):  
Audrey Maheu ◽  
Islem Hajji ◽  
François Anctil ◽  
Daniel F. Nadeau ◽  
René Therrien

Abstract. Total terrestrial evaporation is a key process to understand the hydrological impacts of climate change given that warmer surface temperatures translate into an increase in the atmospheric evaporative demand. To simulate this flux, many hydrological models rely on the concept of potential evaporation (PET) although large differences have been observed in the response of PET models to climate change. The Maximum Entropy Production (MEP) model of land surface fluxes offers an alternative approach to simulate terrestrial evaporation in a simple and parsimonious way while fulfilling the physical constraint of energy budget closure and providing a distinct estimation of evaporation and transpiration. The objective of this work is to use the MEP model to integrate energy budget modeling within a hydrological model. We coupled the MEP model with HydroGeoSphere, an integrated surface and subsurface hydrologic model. As a proof-of-concept, we performed one-dimensional soil column simulations at three sites of the AmeriFlux network. The coupled HGS-MEP model produced realistic simulations of soil water content (RMSE between 0.03 and 0.05 m3 m−3, NSE between 0.30 and 0.92) and terrestrial evaporation (RMSE between 0.31 and 0.71 mm day−1, NSE between 0.65 and 0.88) under semiarid, Mediterranean and temperate climates. HGS-MEP outperformed the standalone HGS model where total terrestrial evaporation is derived from potential evaporation which we computed using the Penman-Monteith equation. This research demonstrated the potential of the MEP model to improve the simulation of total terrestrial evaporation in hydrological models, including for hydrological projections under climate change.


2021 ◽  
Author(s):  
Lirong Ding ◽  
Zhiyong Long ◽  
Ji Zhou ◽  
Shaofei Wang ◽  
Xiaodong Zhang

<p>The downward longwave radiation (DLR) is a critical parameter for radiation balance, energy budget, and water cycle studies at regional and global scales. The accurate estimation of the all-weather DLR with a high temporal resolution is important for the estimation of the surface net radiation and evapotranspiration. However, the most DLR products involve instantaneous DLR estimates based on polar orbiting satellite data under clear-sky conditions. To obtain an in-depth understanding of the performances of different models in the estimation of the DLR over the Tibetan Plateau, which is a focus area of climate change study, this study tested eight methods under clear-sky conditions and six methods under cloudy conditions based on ground-measured data. The results show that the Dilley and O’Brien model and the Lhomme model are most suitable under clear-sky conditions and cloudy conditions, respectively. For the Dilley and O’Brien model, the average root mean square error (RMSE) of the DLR under clear-sky conditions is approximately 22.5 W/m<sup>2</sup> at nine ground sites; for the Lhomme model, the average RMSE is approximately 23.2 W/m<sup>2</sup>. Based on the estimated cloud fraction and meteorological data provided by the China land surface data assimilation system (CLDAS), the hourly all-weather daytime DLR with 0.0625° over the Tibetan Plateau was estimated. The results show that the average RMSE of the estimated hourly all-weather DLR was approximately 26.4 W/m<sup>2</sup>. With the combined all-weather DLR model, the hourly all-weather daytime DLR dataset with a 0.0625° resolution from 2008 to 2016 over the Tibetan Plateau was generated. This dataset can better contribute to studies associated with the radiation balance and energy budget, water cycle, and climate change over the Tibetan Plateau.</p>


2020 ◽  
Author(s):  
Partha Pratim Gogoi ◽  
Velu Vinoj

<p>The impact of local climate change induced by urbanization or changes in the Land Use and Land Cover (LULC) has been contributing as much as ~50% of the total rise in surface air temperature over the Eastern Indian state of Odisha. While analysing the physical mechanism of such rise, it is found that the changes in the specific heat capacity of the surface regulates the changes in the surface energy budget of the region. A slight change in the energy budget may significantly disturb the regional/local climate balance thereby simulating the primary meteorological parameters such as the temperature and surface heat fluxes. LULC which characterises the surface properties can contribute immensely to the energy budget cycle through biophysical and biochemical processes like evaporation, evapotranspiration, shortwave and long wave radiation, absorption and reflection. In this study, we used observational and modeling techniques to quantify the ramifications of LULC changes on the climate of Odisha during the period 2004-2015. A significant change in the spatial pattern of temperature has been observed towards the eastern part of the region.  We try to find out whether this shift in temperature pattern is because of LULC or global climate forcing. Significant diversification in the agricultural practices have also been noticed in the region in the recent times.  To evaluate such effects, Weather Research and Forecasting (WRF) mesoscale modeling system has been enforced to visualize how significantly changes in LULC have impacted parameters like surface temperature, heat fluxes, humidity etc. However, the modeling results also follow consistency with that of the observational signatures and a rise of ~0.5-1.0 <sup>o</sup>C has been observed. Along with the spatial analysis, vertical profiles are also studied where we found significant impact of changed LULC on specific humidity and temperature. This study discusses the dynamics of land-atmosphere interactions instigated by local LULC effects.</p><p><strong>Keywords</strong>: LULC, urbanization, remote sensing, numerical modeling, climate change </p>


2008 ◽  
Vol 148 (12) ◽  
pp. 1990-2005 ◽  
Author(s):  
Hotaek Park ◽  
Takeshi Yamazaki ◽  
Kazukiyo Yamamoto ◽  
Takeshi Ohta

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