Guohua Liu

Dr. Guohua Liu


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 December 2021 in Diversity and Distributions
Verified
Journal Article
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YSYu Shen
Yu Shen
GLGuohua Liu
Guohua Liu
WZWei Zhou
Wei Zhou
YLYuqing Liu
Yuqing Liu
HCHao Cheng
Hao Cheng
XSXukun Su
Xukun Su
Aim: Although protected areas (PAs) are assumed to reduce natural threats within boundaries, their spillover effects remain equivocal. It is necessary to determine whether PAs truly achieve conservation targets and whether they promote or inhibit natural habitat degradation in adjacent areas by blockage or leakage spillover. This study aims to choose 54 nature reserves (NRs) focusing on forest protection as a case study to assess PA conservation effectiveness and spillover prevalence.Location: PAs on the Qinghai‐Tibet Plateau (QTP).Methods: We used matching methods to compare deforestation rates inside PAs and their 20 km buffer zones with matched control areas based on the Global Forest Change dataset from 2001 to 2019. We contrasted the effects of NRs with different management levels, ages and areas. We designed five concentric buffer zones to assess spillover change with distance and estimated potential drivers of the spillover effect to explain its directions and magnitudes.Results: 75.9% of the NRs were effective in preventing deforestation within their boundaries. NRs with different properties showed similar performance on forest conservation. Spillover effects were heterogeneous around NRs. One hundred and twenty‐two buffer zones had positive spillover ranging from 0.1% to 5.3%. One hundred and nineteen buffer zones had leakages from −8.84% to −0.1%. Blockages slightly outnumbered leakages at different distances, while leakages happened more frequently when we treated buffer zones as a whole spillover area. The linear model indicated NR age and population density of buffer zones were the most relevant predictors to spillover value.Main conclusions: Most PAs performed well in forest conservation. Leakages could undermine or offset PA conservation efforts and were related to multiple natural or socio‐economic factors. We recommend considering the plurality of PAs as well as spillover effect and incorporating a social‐ecological framework in further PA establishment and management.

17 May 2022 in Remote Sensing
Verified
Journal Article
Open access
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HLHongyuan Li
Hongyuan Li
GLGuohua Liu
Guohua Liu
CHChuntan Han
Chuntan Han
YYYong Yang
Yong Yang
RCRensheng Chen
Rensheng Chen
Understanding the spatio-temporal variations in the frost-free period (FFP) and the number of frost days (FD) is beneficial to reduce the harmful effects of climate change on agricultural production and enhancing agricultural adaptation. However, the spatio-temporal variations in FFP and FD and their response to climate change remain unclear across China. To investigate the impact of climate change on FFP and FD, the trends and variations in FFP and FD across China from 1950 to 2020 were quantified using ERA5-Land, a reanalysis dataset with high spatial and temporal resolution. The results showed that ERA5-Land has good applicability in quantifying the trends and variations in FFP and FD across China under climate change. The spatial distribution of multi-year average FFP and FD across China showed significant latitudinal zonality and altitude dependence, i.e., FFP decreased with increasing latitude and altitude, while FD increased with increasing latitude and altitude. As a result of climate warming across China, the FFP showed an increasing trend with an increase rate of 1.25 d/10a and the maximum increasing rate of FFP in the individual region was 6.2 d/10a, while the FD showed a decreasing trend with a decrease rate of 1.41 d/10a and the maximum decreasing rate of FD in the individual region was −6.7 d/10a. Among the five major climate zones in China, the subtropical monsoon climate zone (SUMZ) with the greatest increasing rate of 1.73 d/10a in FFP, while the temperate monsoon climate zone (TEMZ) with the greatest decreasing rate of −1.72 d/10a in FD. In addition, the coefficient of variation (Cv) of FFP showed greater variability at higher altitudes, while the Cv of FD showed greater variability at lower latitudes in southern China. Without considering the adaptation to temperature of crops, a general increase in FFP and a general decrease in FD were both beneficial to agricultural production in terms of FFP and FD promoting a longer growing period and reducing frost damage on crops. This study provides a comprehensive understanding of the trends and variations in FFP and FD under climate change, which is of great scientific significance for the adjustment of the agricultural production layout to adapt to climate change in China.

14 August 2021 in Water
Verified
Journal Article
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GLGuohua Liu
Guohua Liu
RCRensheng Chen
Rensheng Chen
KLKailu Li
Kailu Li
Glacial changes have great effects on regional water security because they are an important component of glacierized basin runoff. However, these impacts have not yet been integrated and evaluated in the arid/semiarid inland river basins of western China. Based on the degree-day glacier model, glacier changes and their hydrologic effects were studied in 12 subbasins in the Shiyang River basin (SYRB), Heihe River basin (HHRB) and Shule River basin (SLRB). The results showed that the glacier area of each subbasin decreased by 16.7–61.7% from 1965 to 2020. By the end of this century, the glacier areas in the three basins will be reduced by 64.4%, 72.0% and 83.4% under the three climate scenarios, and subbasin glaciers will disappear completely after the 2070s even under RCP2.6. Glacial runoff in all subbasins showed a decreasing–increasing–decreasing trend, with peak runoff experienced in 11 subbasins during 1965~2020. The contribution of glacial meltwater to total runoff in the basin ranged from 1.3% to 46.8% in the past, and it will decrease in the future due to increasing precipitation and decreasing glacial meltwater. However, the scale differences in glacier runoff are significant when aggregated over the region/basin/subbasin. This suggests that the results of large-scale generalization may be misleading for subbasin glacier water resource evaluations. Therefore, the hydrological effects of glaciers should be studied more in subbasins to provide an accurate reference for practical water resource management.

10 April 2019 in Remote Sensing
Verified
Journal Article
Open access
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LWLei Wang
Lei Wang
RCRensheng Chen
Rensheng Chen
CHChuntan Han
Chuntan Han
YYYong Yang
Yong Yang
JLJunfeng Liu
Junfeng Liu
SGShuhai Guo
Shuhai Guo
Remote sensing techniques provide data on the spatial–temporal distribution of environmental parameters over regions with sparse ground observations. However, the resolution of satellite precipitation data is too coarse to be applied to hydrological and meteorological research at basin scales. Downscaling research using coarse remote sensing data to obtain high-resolution precipitation data is significant for the development of basin-scale research. Here, we propose improvements to a spatial–temporal method for downscaling satellite precipitation. The improved method uses a nonlinear regression model and introduces longitude and latitude based on processed normalized difference vegetation index (NDVI) and a digital elevation model (DEM) to stimulate precipitation in the Qilian Mountains during 2006–2015. The final downscaled annual precipitation (FDAP) results are corrected by observed data to obtain corrected final downscaled annual precipitation (CFDAP) datasets. For temporal downscaling, monthly downscaled data are the corrected monthly ratio multiplied by the corresponding downscaled annual datasets. The results indicated that processed NDVI (PNDVI) reflected spatial precipitation patterns more accurately than the original NDVI. The accuracy was significantly improved when the final downscaled annual precipitation data were corrected by observed data. The average annual root mean square error (RMSE) from 2006 to 2015 of CFDAP was 66.48 and 83.07 mm less than that of FDAP and original Tropical Rainfall Measuring Mission (TRMM) data, respectively. Compared with previous methods, which use NDVI and/or DEM to downscale TRMM, the accuracy of FDAP and CFDAP from the improved method was higher, and the RMSE decreased on average by 13.63 and 80.11 mm. The RMSE of monthly data from corrected monthly ratio (CMR) decreased on average by 4.93 mm over monthly data from previous monthly ratio (PMR). In addition, the accuracy of the original satellite data affected the initial downscaling results but had no significant effects on the corrected downscaling results.

29 November 2021 in Earth and Space Science
Verified
Journal Article
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SGShuhai Guo
Shuhai Guo
RCRensheng Chen
Rensheng Chen
CHChuntan Han
Chuntan Han
JLJunfeng Liu
Junfeng Liu
XWXiqiang Wang
Xiqiang Wang
GLGuohua Liu
Guohua Liu
As a principal pathway of moisture loss of cryosphere, the sublimation of snow or ice needs to absorb a high amount of energy to complete the phase transition, while related researches on how sublimation affects surface energy balance (SEB) are still insufficient, causing unclear conclusions. To characterize the seasonal variation of a mountain glacier's sublimation or evaporation and analysis its role on SEB, the meteorological and glaciological data over five‐year measurement period (2016–2020) were obtained on the top of August‐one glacier. In the non‐melt period of a year (January–May and October–December), sensible heat flux H was the dominant energy contributor to glacier surface (76%), followed by net radiation R net (22%). Sublimation removed average 85 mm (0.4 mm/day) of water vapor from surface for the dry and windy weather, and the latent heat flux of sublimation LEE accounted for 33% of energy sinks (67% of energy was stored in the glacier Q s ). In the melt period (June–September), evaposublimation (mainly composed of evaporation) reached to 36 mm (0.3 mm/day), but LEE only played a small heat sink (14%) and the Q m (the energy for melting) had the largest proportion (70%). R net and H contributed 81% and 15% of surface energy, respectively. Obviously, under the global climate warming, the sublimation of non‐melt period seems to be effective in decrease the heating rate of glacier surface.

6 January 2021 in Water
Verified
Journal Article
Open access
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KLKailu Li
Kailu Li
RCRensheng Chen
Rensheng Chen
GLGuohua Liu
Guohua Liu
Water is the most critical factor that restricts the economic and social development of arid regions. It is urgent to understand the impact on cryospheric changes of water resources in arid regions in western China under the background of global warming. A cryospheric basin hydrological model (CBHM) was used to simulate the runoff, especially for glaciers and snowmelt water supply, in the Shiyang River Basin (SRB). A cryosphere water resources service function model was proposed to evaluate the value of cryosphere water resources. The annual average temperature increased significantly (p > 0.05) from 1961 to 2016. The runoff of glacier and snowmelt water in the SRB decreased significantly. This reduction undoubtedly greatly weakens the runoff regulation function. The calculation and value evaluation of the amount of water resources in the cryosphere of Shiyang River Basin is helpful to the government for adjusting water structure to realize sustainable development.