scholarly journals Interdecadal Changes in the Freeze Depth and Period of Frozen Soil on the Three Rivers Source Region in China from 1960 to 2014

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Siqiong Luo ◽  
Xuewei Fang ◽  
Shihua Lyu ◽  
Qi Jiang ◽  
Jingyuan Wang
Keyword(s):  
Air Temperature ◽  
Snow Depth ◽  
Source Region ◽  
Frozen Soil ◽  
Depth Data ◽  
Temperature And Precipitation ◽  
Period 2 ◽  
Three Rivers ◽  
Increasing Trends ◽  
Freeze Duration

On the basis of observed soil freeze depth data from 14 meteorological stations on the Three Rivers Source Region (TRSR) in China during 1960 to 2014, trends in the freeze depth, first date, last date, and duration of frozen soil were analyzed, together with other meteorological variables, such as air temperature, snow depth, and precipitation, observed at the same locations. The results showed the following. (1) A continuous, accelerated decreasing trend in freeze depth appeared in the TRSR during the 1985–2014 and 2000–2014 periods, compared with that during the 1960–2014 period. (2) The freeze first date had been delayed and the freeze last date had been advanced significantly. The advanced trends in freeze last date were more significant than the delayed trends in freeze first date. The freeze duration also experienced an accelerated decrease. (3) The freeze depth and period were strongly affected by air temperature, thawing index, and soil moisture (precipitation), but not by snow. The freeze depth, freeze first date, freeze last date, and duration also influenced each other. (4) These decreasing trends in freeze depth and duration are expected to continue given the increasing trends in air temperature and precipitation in this region.

Increasing trends in rainfall-runoff erosivity in the Source Region of the Three Rivers, 1961–2012

2017 ◽  
Vol 592 ◽  
pp. 639-648 ◽  
Author(s):  
Yousheng Wang ◽  
Congcong Cheng ◽  
Yun Xie ◽  
Baoyuan Liu ◽  
Shuiqing Yin ◽  
...  
Keyword(s):  
Source Region ◽  
Rainfall Runoff ◽  
Three Rivers ◽  
Increasing Trends

scholarly journals Analyses of Climate Variations at Four Meteorological Stations on Remote Islands in the Croatian Part of the Adriatic Sea

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1044
Author(s):  
Ognjen Bonacci ◽  
Matko Patekar ◽  
Marco Pola ◽  
Tanja Roje-Bonacci
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Water Resources ◽  
Air Temperature ◽  
Climate Models ◽  
Adriatic Sea ◽  
Temperature And Precipitation ◽  
Intensive Exploitation ◽  
Increasing Trends ◽  
The Impact

The Mediterranean region is one of the regions in the world that is most vulnerable to the impact of imminent climate change. In particular, climate change has an adverse effect on both the ecosystem and socioeconomic system, influencing water availability for both human and environmental purposes. The most endangered water resources are along the coasts and on islands since they have relatively small volumes and are intensively exploited. We analyzed the time series of air temperature and precipitation measured at four meteorological stations (Komiža, Palagruža, Lastovo, and Biševo) located on small islands in the Croatian part of the Adriatic Sea in this study. The investigated time series extend from the 1950s to the present, being contemporaneous for approximately 50 years. Despite possessing discontinuity, they can be considered as representative for assessing climate change and variability in the scattered environment of the Croatian islands. The results showed increasing trends in the annual air temperature, while the annual cumulative precipitation did not show significant variations. In addition, the analyses of the monthly air temperature showed that statistically significant increasing trends occurred from April to August, suggesting a more severe impact during these months. These results are in accordance with regional and local studies and climate models. Although the climate variability during the analyzed period can be considered as moderate, the impact on water resources could be severe due to the combined effect of the increase in air temperature during warm periods and the intensive exploitation for tourism purposes.

Spatial and Temporal Patterns of Net Primary Productivity in the Source Regions of Yangtze and Yellow Rivers

2012 ◽  
Vol 518-523 ◽  
pp. 5130-5137
Author(s):  
Zhao Ping Yang ◽  
Ji Xi Gao ◽  
Mei Rong Tian
Keyword(s):  
Air Temperature ◽  
Net Primary Productivity ◽  
Yellow River ◽  
Net Primary Production ◽  
Source Region ◽  
Northwestern Part ◽  
Climatic Data ◽  
Spatial And Temporal Patterns ◽  
Temperature And Precipitation ◽  
Source Regions

Based on remote sensing data, climatic data and other related data in source regions of the Yangtze and Yellow Rivers from 2000 to 2006, the net primary production (NPP) of source regions of the Yangtze and Yellow Rivers was estimated by using CASA (Camegie-Ames-Stanford Approach) model. Spatial pattern and changing tendency for vegetation NPP, and correlation relationships between air temperature, precipitation and NPP were analyzed. The results showed that annual average NPP in source regions of Yangze and Yellow Rivers was 104.22 gC.m-2.a-1. A total mean annual NPP in source regions of Yangtze and Yellow Rivers was 22.07×1012g C.a-1, which decreased from southeastern to northwestern part and this trend coupled with the changes in temperature and precipitation. Increasing trend of NPP in source region of Yellow River was clearer than that in source region of Yangze River during 2000-2006. The region with increasing tendency occupied approximately 68.42% of total area, while the region with decreasing tendency accounted for 23.83%. Marked decrease regions for NPP were mainly distributed in the southeastern source region of the Yellow River including Gande county, Dari county, Maqin county and area nearby Dari river and Kequ, occupied 10.56% of total source regions area. The region of very marked increase sporadically distributed in the region with marked increase trend. The northwestern region of Yellow River and southeastern region of Yangtze River were located by region with indistinct increase extensively. Regression analysis of vegetation NPP and climate factors showed that average temperature and precipitation were important factors affecting changes in vegetation NPP; while the mean air temperature appears to be the primary factor controlling terrestrial NPP in the source regions of Yangze and Yellow rivers.

scholarly journals Variations and changes in snow depth at meteorological stations Barentsburg and Hornsund (Spitsbergen)

2017 ◽  
Vol 58 (75pt1) ◽  
pp. 11-20 ◽  
Author(s):  
Marzena Osuch ◽  
Tomasz Wawrzyniak
Keyword(s):  
Snow Cover ◽  
Interannual Variability ◽  
Trend Analysis ◽  
Air Temperature ◽  
Snow Depth ◽  
Moving Average ◽  
Onset Date ◽  
The Novel ◽  
Temperature And Precipitation ◽  
Snow Cover Duration

ABSTRACTIn this study, seasonality and interannual variability of snow depth at two stations (Hornsund and Barentsburg) located in western Spitsbergen are investigated. For this purpose, the novel Moving Average over Shifting Horizon method combined with trend estimation was used. The Hornsund and Barentsburg stations exhibit similar snow depth trends during early autumn and late spring when statistically significant decreases were estimated at both stations (for August 1984–July 2016). In the remaining period, there are differences in outcomes between stations. The results for Barentsburg from October till the end of May are characterised by the lack of a trend while at Hornsund decreases of snow depth were estimated. The largest changes occur in May when the snow depth was at its maximum. Differences in the estimated tendencies were explained with the help of a trend analysis for air temperature and precipitation. An analysis of maximum snow depth, snow onset date, snow disappearance date and snow-cover duration is included. The results of the assessment depend on the location, with a lack of statistically significant changes in Barentsburg, and later snow onset date, shorter duration and decrease of maximum depth in Hornsund.

scholarly journals Assimilation of D-InSAR snow depth data by an ensemble Kalman filter

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Jinming Yang ◽  
Chengzhi Li
Keyword(s):  
Remote Sensing ◽  
Kalman Filter ◽  
Water Resource ◽  
Ensemble Kalman Filter ◽  
Snow Depth ◽  
Resource Assessment ◽  
Measured Data ◽  
Hydrological Process ◽  
Depth Data ◽  
Water Resource Assessment

AbstractSnow depth mirrors regional climate change and is a vital parameter for medium- and long-term numerical climate prediction, numerical simulation of land-surface hydrological process, and water resource assessment. However, the quality of the available snow depth products retrieved from remote sensing is inevitably affected by cloud and mountain shadow, and the spatiotemporal resolution of the snow depth data cannot meet the need of hydrological research and decision-making assistance. Therefore, a method to enhance the accuracy of snow depth data is urgently required. In the present study, three kinds of snow depth data which included the D-InSAR data retrieved from the remote sensing images of Sentinel-1 synthetic aperture radar, the automatically measured data using ultrasonic snow depth detectors, and the manually measured data were assimilated based on ensemble Kalman filter. The assimilated snow depth data were spatiotemporally consecutive and integrated. Under the constraint of the measured data, the accuracy of the assimilated snow depth data was higher and met the need of subsequent research. The development of ultrasonic snow depth detector and the application of D-InSAR technology in snow depth inversion had greatly alleviated the insufficiency of snow depth data in types and quantity. At the same time, the assimilation of multi-source snow depth data by ensemble Kalman filter also provides high-precision data to support remote sensing hydrological research, water resource assessment, and snow disaster prevention and control program.

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