Stream Temperature Impacts Because of Changes in Air Temperature, Land Cover and Stream Discharge: Navarro River Watershed, California, USA

2016 ◽  
Vol 32 (10) ◽  
pp. 2020-2031 ◽  
Author(s):  
C. J. Woltemade ◽  
T. W. Hawkins
Keyword(s):  
Land Cover ◽  
Air Temperature ◽  
Stream Temperature ◽  
River Watershed ◽  
Stream Discharge ◽  
Temperature Impacts

scholarly journals Quantifying the Independent Influences of Land Cover and Humidity on Microscale Urban Air Temperature Variation in Hot Summer: Methods of Path Analysis and Genetic SVR

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Land Cover ◽  
Path Analysis ◽  
Temperature Variation ◽  
Direct Effect ◽  
Air Temperature ◽  
Urban Areas ◽  
Support Vector ◽  
Urban Air ◽  
Air Temperatures

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.

scholarly journals Biogeophysical impacts of peatland forestation on regional climate changes in Finland

2014 ◽  
Vol 11 (24) ◽  
pp. 7251-7267 ◽  
Author(s):  
Y. Gao ◽  
T. Markkanen ◽  
L. Backman ◽  
H. M. Henttonen ◽  
J.-P. Pietikäinen ◽  
...  
Keyword(s):  
Land Cover ◽  
Air Temperature ◽  
Surface Albedo ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Air Temperature ◽  
Forest Growth ◽  
Background Information ◽  
Snow Melting ◽  
Melting Period

Abstract. Land cover changes can impact the climate by influencing the surface energy and water balance. Naturally treeless or sparsely treed peatlands were extensively drained to stimulate forest growth in Finland over the second half of 20th century. The aim of this study is to investigate the biogeophysical effects of peatland forestation on regional climate in Finland. Two sets of 18-year climate simulations were done with the regional climate model REMO by using land cover data based on pre-drainage (1920s) and post-drainage (2000s) Finnish national forest inventories. In the most intensive peatland forestation area, located in the middle west of Finland, the results show a warming in April of up to 0.43 K in monthly-averaged daily mean 2 m air temperature, whereas a slight cooling from May to October of less than 0.1 K in general is found. Consequently, snow clearance days over that area are advanced up to 5 days in the mean of 15 years. No clear signal is found for precipitation. Through analysing the simulated temperature and energy balance terms, as well as snow depth over five selected subregions, a positive feedback induced by peatland forestation is found between decreased surface albedo and increased surface air temperature in the snow-melting period. Our modelled results show good qualitative agreements with the observational data. In general, decreased surface albedo in the snow-melting period and increased evapotranspiration in the growing period are the most important biogeophysical aspects induced by peatland forestation that cause changes in climate. The results from this study can be further integrally analysed with biogeochemical effects of peatland forestation to provide background information for adapting future forest management to mitigate climate warming effects. Moreover, they provide insights about the impacts of projected forestation of tundra at high latitudes due to climate change.

Indian River Watershed Image Analysis Using Fuzzy-CA Hybrid Approach

2017 ◽  
pp. 232-246
Author(s):  
Kalyan Mahata ◽  
Subhasish Das ◽  
Rajib Das ◽  
Anasua Sarkar
Keyword(s):  
Cellular Automata ◽  
Land Cover ◽  
Discrete Dynamical System ◽  
Hybrid Approach ◽  
Ground Truth ◽  
Second Phase ◽  
River Watershed ◽  
Set Membership ◽  
Mixed Pixels ◽  
Indian River

Image segmentation among overlapping land cover areas in satellite images is a very crucial task. Detection of belongingness is the important problem for classifying mixed pixels. This paper proposes an approach for pixel classification using a hybrid approach of Fuzzy C-Means and Cellular automata methods. This new unsupervised method is able to detect clusters using 2-Dimensional Cellular Automata model based on fuzzy segmentations. This approach detects the overlapping regions in remote sensing images by uncertainties using fuzzy set membership values. As a discrete, dynamical system, cellular automaton explores uniformly interconnected cells with states. In the second phase of our method, we utilize a 2-dimensional cellular automata to prioritize allocations of mixed pixels among overlapping land cover areas. We experiment our method on Indian Ajoy river watershed area. The clustered regions are compared with well-known FCM and K-Means methods and also with the ground truth knowledge. The results show the superiority of our new method.

scholarly journals Evidence and impact of map error on land use and land cover dynamics in Ashi River watershed using intensity analysis

PLoS ONE ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. e0229298 ◽  
Author(s):  
Vitus Tankpa ◽  
Li Wang ◽  
Raphael Ane Atanga ◽  
Alfred Awotwi ◽  
Xiaomeng Guo
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Intensity Analysis ◽  
River Watershed ◽  
Land Cover Dynamics

Comparison of PMP-Driven Probable Maximum Floods with Flood Magnitudes due to Increasingly Urbanized Catchment: The Case of American River Watershed

2013 ◽  
Vol 17 (8) ◽  
pp. 1-15 ◽  
Author(s):  
Wondmagegn Yigzaw ◽  
Faisal Hossain ◽  
Alfred Kalyanapu
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Design Procedure ◽  
Sensitivity Study ◽  
The Other ◽  
Design Flood ◽  
Climatic Effects ◽  
River Watershed ◽  
Other Hand ◽  
American River

Abstract Since historical (predam) data are traditionally the sole criterion for dam design, future (postdam) meteorological and hydrological variability due to land-use and land-cover change cannot be considered for assessing design robustness. For example, postdam urbanization within a basin leads to definite and immediate increase in direct runoff and reservoir peak inflow. On the other hand, urbanization can strategically (i.e., gradually) alter the mesoscale circulation patterns leading to more extreme rainfall rates. Thus, there are two key pathways (immediate or strategic) by which the design flood magnitude can be compromised. The main objective of the study is to compare the relative contribution to increase in flood magnitudes through direct effects of land-cover change (urbanization and less infiltration) with gradual climate-based effects of land-cover change (modification in mesoscale storm systems). The comparison is cast in the form of a sensitivity study that looks into the response to the design probable maximum flood (PMF) from probable maximum precipitation (PMP). Using the American River watershed (ARW) and Folsom Dam as a case study, simulated peak floods for the 1997 (New Year's) flood event show that a 100% impervious watershed has the potential of generating a flood that is close to design PMF. On the other hand, the design PMP produces an additional 1500 m3 s−1 peak flood compared to the actual PMF when the watershed is considered 100% impervious. This study points to the radical need for consideration future land-cover changes up front during the dam design and operation formulation phase by considering not only the immediate effects but also the gradual climatic effects on PMF. A dynamic dam design procedure should be implemented that takes into account the change of land–atmospheric and hydrological processes as a result of land-cover modification rather than relying on historical records alone.

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