Subjects: Geosciences >> Geography submitted time 2025-07-14 Cooperative journals: 《干旱区研究》
Abstract： Nitrous oxide (N2O) a remarkable greenhouse gas in the atmosphere, exerts a pronounced effect on global climate warming. Changes in land use types critically affects N2O emissions, particularly in ecologically fragile semiarid regions with more complex underlying mechanisms. However, there is still a lack of systematic research on how complex and diverse land use types affect soil N2O emissions in semiarid regions of China and the key driving factors involved. To address this, this study focused on four typical land use types in the semiarid Loess Plateau of central Gansu Province: Picea asperata forest (Piceaasperata); Medicago sativa grassland (Medicago sativa); abandoned land (Abandoned land); and wheat field (Wheat field). Soil N2O fluxes were monitored using the static chamber-gas chromatography method, combined with soil physicochemical property data,to elucidate the key drivers regulating soil N2O emissions under different land use types. Compared to the abandoned land, the Picea asperata forest and Medicago sativa grassland had significantly increased soil water content, while wheat fields exhibited elevated ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) concentrations. Compared to the abandoned land, the Medicago sativa grassland and wheat fields exhibited markedly enhanced nitrate reductase and nitrite reductase activities, which decreased with an increase in soil depth across all treatments. Soil N2O fluxes under different land use types exhibited an initial increase followed by a decline during the vegetation growth stages. The total soil N2O emissions decreased by 34.2% and 23.3% in the Picea asperata forest and Medicago sativa grassland, respectively, and increased by 32.47% in the wheat fields, compared to the abandoned land. Random forest analysis identified soil temperature as the most influential factor affecting the soil N2O flux. Overall, compared to the abandoned land and wheat fields, the artificial forest and grassland systems in the study area demonstr
Subjects: Geosciences >> Geography submitted time 2025-07-14 Cooperative journals: 《干旱区研究》
Abstract： The Loess Plateau (LP) in China is highly sensitive to climate change, making it an ideal region for understanding temperature dynamics under global warming. This study analyzed the spatio-temporal variations of integrated temperature indicators for ≥0 ℃ and ≥10 ℃—including the first date (FD); ending data (ED); duration (DD); and active integrated temperature (AIT)—using daily average temperature data from 55 meteorological stations on the LP spanning 1960 to 2019. Methods such as linear fitting, mutation tests, and dominance analysis were employed. The results indicate that, from 1960 to 2019, the indicators for both thresholds changed synchronously, with an advancing FD, a delayed ED, a prolonged DD, and an increasing AIT (P<0.01). Notably, most interdecadal shifts occurred in the 1990s, with abrupt changes concentrated from the late 1990s to the early 2000s. The spatial distribution of mean values for both thresholds was similar, showing that FD advanced, ED delayed, DD prolonged, and AIT increased from northwest to southeast. However, the spatial trends differed: the magnitude of the ED delay followed an east-west pattern with alternating phases, while the increase in AIT was higher in the east and lower in the west. For the ≥0 ℃ threshold, changes in FD, ED, and DD were influenced jointly by latitude and altitude, whereas changes in the other indicators were mainly driven by altitude, with contribution rates between 65.59% and 72.17%. The contribution of FD changes to DD changes was 65.1% for ≥0 ℃ and 68.4% for ≥10 ℃, each exhibiting opposite spatial distribution patterns. Compared with 1960-1989, most indicators—except DD and AIT for ≥0 ℃ and FD for ≥10 ℃—showed significant shifts (in terms of earlier or delayed timing, extended duration, or increased magnitude) during 1990-2019, with more pronounced changes at the ≥0 ℃ threshold. Furthermore, the contribution of FD change to DD change decreased by 2.3% for ≥0 ℃ but increased by 15.2% for ≥10 ℃. Spatially, the variation in contribution rates exhibited a“higher-lower-higher”pattern along the south-to-west axis and a contrast with higher values in the southeast and lower in the northwest. Overall, the integrated temperature indicators for both thresholds on the LP show significant responses to climate warming, with distinct regional and temporal characteristics.
Subjects: Geosciences >> Geography submitted time 2025-07-06 Cooperative journals: 《干旱区地理》
Abstract：全球变暖趋势下，黄土高原极端气候事件频发，明确黄土高原极端降水事件的时空特征对区域灾害防范具有重要意义。基于1960—2023年黄土高原111个气象站点的日降水数据，通过去趋势波动分析（DFA）法确定极端降水阈值来识别极端降水事件，采用Mann-Kendall检验等方法分析黄土高原全区及生态分区的极端降水事件特征。结果表明：（1）黄土高原各气象站的极端降水阈值介于27.4~89.1 mm，有54%站点的阈值>50 mm，各生态分区的平均阈值介于35.0~59.6 mm之间，呈西北低、东南高的分布特征。（2）极端降水事件的降水量及强度分别从西北部的10.6 mm·a-1、33.0 mm·d-1增至东南部的71.5 mm·a-1、133.0 mm·d-1，其发生频率则从北部的0.3 d·a-1增至南部的0.8 d·a-1。极端降水日数更接近于暴雨日数，特别是在黄土丘陵沟壑区B2副区。（3）黄土高塬沟壑区、土石山区及河谷平原区是极端降水事件的高发区，应作为灾害防治重点区域。（4）近64 a的极端降水事件具有明显的年际波动特征，全区的极端降水事件增多，集中在7、8月。（5）近10 a来，黄土高塬沟壑区、黄土丘陵沟壑区的极端降水事件的降水量及频率有所增多；沙地和农灌区的极端降水事件下降趋势减缓，而土石山区及河谷平原区的极端降水事件在2020年发生突变且增多。研究结果为黄土高原各生态分区极端降水事件的防灾减灾提供了参考依据。
Subjects: Geosciences >> Geography submitted time 2025-03-14 Cooperative journals: 《干旱区地理》
Abstract：识别对于维护区域生态系统具有重要意义的点、线、面等景观要素，构建动态生态安全格局并探究其影响因素，对于维护区域生态安全具有重要意义。针对以往研究对生态安全格局动态演化和影响因素探究的不足，利用形态空间格局分析（MSPA）、景观连通性分析和电路理论模型等方法，构建2000—2020年陕北黄土高原的生态安全格局，分析其时空演化特征，并利用地理探测器、普通最小二乘法（OLS）和地理加权回归（GWR）模型探究生态安全格局空间异质性的影响因素，并给出生态恢复策略。结果表明：（1）2000—2020年生态源地在陕北黄土高原南部集中分布，面积变化较小且空间位置较为稳定。（2）2000、2010年和2020年陕北黄土高原生态阻力面的均值分别为4.96、4.36和4.40，呈现南部低、西北高的空间格局。（3）2000、2010年和2020年陕北黄土高原生态廊道的长度分别为2416.25 km、3433.61 km和2643.62 km，南部生态廊道密集，以低阻力生态廊道为主，北部生态廊道稀疏，以高阻力生态廊道为主。（4）生态夹点和生态障碍点主要分布在陕北黄土高原西北部，面积不断减少。（5）植被覆盖度、景观多样性、人口密度、坡度和降水是影响陕北黄土高原生态安全格局空间异质性的主要因子。研究结果可为陕北黄土高原未来的生态规划提供科学合理的参考和依据，同时有助于生态政策的制定与调整。
Subjects: Geosciences >> Geography submitted time 2025-03-14 Cooperative journals: 《干旱区地理》
Abstract：量化生态系统服务时空变化，探究生态系统服务的权衡效应及其影响因素，有利于促进区域生态功能恢复。以陇东黄土高原为例，基于InVEST模型对产水量、粮食供给、土壤保持和固碳4种重要生态系统服务进行评估，采用Sen+Mann-Kendall方法识别该地区2001—2020年生态系统服务时空变化趋势，运用相关系数和均方根偏差量化生态系统服务权衡效应，并利用地理探测器探究其驱动因素。结果表明：（1）近20 a陇东黄土高原产水量、粮食供给和土壤保持整体表现为不显著增加，固碳呈现显著增加态势。（2）生态系统服务间权衡效应在不同地区各有差异，产水量与粮食供给权衡关系主要集中在陇东黄土高原东南部，粮食供给与土壤保持权衡关系分布在陇东黄土高原南部，且权衡度有下降趋势，粮食供给与固碳权衡度有明显的上升趋势。（3）生态系统服务权衡效应受自然因素和人为因素共同作用，其中年降水量是关键的驱动因素。研究从生态系统服务权衡效应的角度为区域生态规划和改善生态系统服务质量提供了科学依据。
Subjects: Geosciences >> Geography submitted time 2024-12-16
Abstract： Climate change has increased the frequency of long-term droughts and heavy rainfall events, impactingecosystems’ carbon cycle. Therefore, understanding how soil enzyme activity in different dry/wet conditions affects organic carbon mineralization can help deepen our understanding of the carbon cycle mechanism and advance the goal of' global carbon neutrality. This study was based on the unique terraces built to control erosion inthe Loess Plateau, and three treatments of flooding stress, drought stress, and wet/dry cycles were designed tomonitor soil enzyme activity and organic carbon mineralization. The results indicate that the wet/dry cycle has atransient stimulating effect on organic carbon mineralization, and the cumulative mineralized organic carbon oc-curs between the drought and flooding stress. At the same time, the wet/dry cycle will increase the activity of car.bon and nitrogen cycle-related enzymes; however, the enzyme activity will gradually decrease and stabilize as thenumber of cycles increases. The enzyme activity in all three water treatment conditions was limited by carbon andphosphorus, and the carbon limitation was more substantial with increasing wet/dry cycles. After the fourth alter.nating wet/dry cycle, the phosphorus limitation exceeded the flooding and drought stress treatments. When thesoil was under drought stress, flooding stress, or wet/dry cycles, the enzyme activity factors that limit organic car.bon mineralization were different. The direct effect of the phosphatase factor under drought stress was 99%, thedirect impact of EAA. (carbon cyele- /nitrogen cycle-related enzyme) and xyloglucosidase factor under floodingstress was 87%, and the direct effect of the interaction between factors under drought and flooding stress was on.ly 1% and 13%. Under wet/dry cycle conditions, the direct impact of phosphatase and N-acetyl-beta-glucosamini.dase factor was 75%, the direct effect of interaction between factors was 25%, and the wet/dry cycle significantlyincreased the interaction between factors. This study provides theoretical support for clarifying the role of LoessTerrace.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Geography submitted time 2024-12-04
Abstract：黄土高原是世界上土壤侵蚀最严重和中国增绿幅度最大的地区，研究该区水分利用效率（WUE）时空演变及其与干旱和地表温度（LST）之间的关系，已成为黄土高原最大植被容纳阈值选择的重要参考。基于Theil-Sen趋势法和一阶差分相对贡献量法分析了2001—2021年黄土高原不同季节WUE时空变化规律及干旱和LST对WUE变化的贡献情况。结果表明：（1）2001—2021年黄土高原春、秋季WUE平均值小于2.0 g C·m-2·mm-1，夏季WUE平均值大于2.0 g C·m-2·mm-1。春、秋季耕地和林地区域WUE高于草地区域，夏季耕地区域WUE最低，林地区域次之，草地区域最高。（2）春、夏季WUE以稳定不变趋势为主，空间分布上均表现为“中部减少，西部和东部稳定不变”的特征，草地区域WUE下降速率>林地区域>耕地区域；秋季WUE以增加趋势为主，草地区域WUE上升速率>林地区域>耕地区域，空间分布上呈“西北增加，东南减少”的特征。（3）春、夏季LST对WUE变化为正贡献度，草地区域表现最为显著，秋季LST对草地和林地区域WUE为负贡献度，但对耕地区域WUE为正贡献度。春、秋季干旱对WUE变化为正贡献度，夏季为负贡献度。以上结果有助于认识气候变化和生态修复工程实施背景下黄土高原干旱和LST与水资源之间的关系。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： Inrecentyears,drasticandextremeformsofsoilerosion,suchaslandslides,mudflows,andsiltdam outbursts,triggeredbyextremerainstormsontheLoessPlateauhaveattractedwidespreadattention.FromOcto- ber3to6,2021,alargeshallowlandslidedisasterwastriggeredbyheavyrainfallalongtheCaijiachuanwater- shedinJixianCounty,ShanxiProvince.Inthisstudy,therainfallprocess,landslideinitiationconditions,andero- sioncharacteristicswereanalyzedusingpredisasterandpostdisasterunmannedaerialvehicleimagery,historical remotesensingimages,andrainfalldataprovidedbytheNationalFieldScientificObservatoryforForestEcosys- temsinJixianCounty,ShanxiProvince.Theresultsshowthatitwasatypical “long-duration,low-intensity” rain- fall,withatotalprecipitationof121.8mminthefirst72hoftheinitiationofthemassive,shallowlandslidesand arainfallintensityof33.2mm·(6h) -1duringtheinitiationofthelandslides.Thelandslidetriggeredbythisrain- stormrequiredaslightlysmallercatchmentareaandexhibitedhigherlandslidemobilitythanthelandslidetrig- geredbyatypicalshort-duration,high-intensityrainstormin2003;however,theslopeofthelandslidewasnot significantlydifferent.Thus,thecumulativerainfallintheearlystagewasthemainfactorinfluencingtheoccur- renceandflexibilityofthemassivelandslidedisaster.Themagnitudeoflandslidenumberprobability,areaproba- bility,anderosionintensityincatchmentswithdifferentlandusetypesdecreasedinthefollowingorder:farmland catchment>plantationforestcatchment>closedcatchment.Thisfindingindicatedthatthelandusetypeandvege- tationcoveraffectthedegreeoflandslideerosiontoacertainextentandthatanarboreal-dominatedwatershedis moreunfavorabletolandslideinitiation.
Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： This study examined the vegetation characteristics and species diversity of mixed herb communities in different years on the slope of expressway in the Loess Plateau, and explored the relationship between herb community characteristics, species diversity, and soil physical and chemical properties. The characteristics of herb communities, α species diversity, and their correlation with soil physical and chemical properties were studied using the Mantel test after 15 a, 12 a, 8 a, 4 a, and 2 a of restoration of herb communities on the highway slope of the Loess Plateau by space instead of time. In total, 13 species of 13 genera in 8 families were investigated in 15 a of slope restoration, 10 species of 10 genera in 7 families were investigated in 12 a of restoration, 5 species of 5 genera in 3 families were investigated in 8 years of restoration, 5 species of 5 genera in 3 families were investigated in 4 a of restoration, and 6 species of 6 genera in 4 families were investigated in 2 a of restoration. Patric species richness recovered in the order 15 a>12 a>8 a>2 a>4 a, the Shannon-Wiener and Simpson indices recovered in the order 15 a>12 a>2 a>8 a>4 a, and the Pielou evenness index recovered in the order 15 a>2 a>8 a>12 a>4 a.Patric species richness was significantly positively correlated with total porosity and capillary porosity, organic matter, total nitrogen, and total phosphorus (P<0.05), and the Shannon-Wiener index was significantly positively correlated with organic matter and total phosphorus (P<0.05). After spraying mixed grass species in different years on the slope, the herb communities mostly contained perennials, but there were differences in species composition and quantity of the community. The species richness, Shannon-Wiener index, and Simpson index of patric species showed an upward trend as the number of restoration years increased. Soil total porosity, capillary porosity,organic matter, total nitrogen, and total phosphorus were the key environmental factors affecting patric species richness and the Shannon-Wiener index.
Subjects: Geosciences >> Geography submitted time 2024-05-20 Cooperative journals: 《干旱区地理》
Abstract：黄土高原水蚀风蚀交错区作为中国北方典型的生态脆弱区，因其独特地形和气候条件，极端降雨事件对其环境和生态系统的影响更加突出。选取水蚀风蚀交错区28个气象站点，结合RClimDex模型计算11个极端降水指数，采用线性相关分析法、Mann-Kendall趋势检验法和小波交叉法，分析了1970—2020年黄土高原水蚀风蚀交错区极端降水事件时空分布特征，探讨了极端降水事件的驱动因素。结果表明：（1）1970—2020年水蚀风蚀交错区持续干燥日数（CDD）呈下降趋势，其余10个指数呈上升趋势，反映出近50 a研究区极端降水事件的频率、量级和强度不断增加。交错区年降水量增加和极端降水事件增加具有密切关系，且极端降水事件增加主要是由中雨日数（R10）和大雨日数（R20）引起。（2）1970—2020年极端降水事件在全区整体为增加趋势，交错区中部和西南部极端降水事件显著发生，陕西段极端降水量和强度呈显著增加趋势且极端化程度更显著。（3）湿日总降水量（PRCPTOT）、暴雨日数（R25）、5 d最大降水量（R5d）3个极端降水指数，与影响因子厄尔尼诺-南方涛动（ENSO）、东亚夏季风（EASM）和太阳黑子（SN）具有不同的功率，与SN的交叉小波变换功率最大，说明影响因子中SN和极端降水指数的相关性最高，SN对极端降水事件的影响最大。
Subjects: Geosciences >> Geography submitted time 2024-04-01 Cooperative journals: 《干旱区地理》
Abstract：开展矿区生态系统服务价值的时空分析对保护矿区生态环境、提升矿区生态系统功能具有重要意义。基于遥感数据和土地利用数据，采用3S技术、价值当量法和生态贡献度等方法，对黄土高原典型矿区——平朔矿区1990—2020年生态系统服务价值进行研究。结果表明：（1）1990—2020年平朔矿区6种土地利用类型面积变化迥异，耕地面积减少最大（1122.72 hm2），建设用地面积增加最大（2044.23 hm2）。（2）平朔矿区生态系统服务价值呈先下降后上升态势，由1990 年的19562.43×104元减少到2010年的11265.40×104元，再增加到2020年的15755.47×104元，1990—2010年下降的主要原因是建设用地和草地的生态系统服务价值大幅减少，2010—2020年增加的主要原因是矿区实施了大量生态恢复治理工程。（3）1990—2020年平朔矿区除保持土壤价值增加外，其他各单项生态服务价值均有不同程度的减少，其中水源涵养、净化环境、生物多样性价值减少幅度较大，分别减少了115.84%、69.92%、18.29%。（4）1990—2020 年平朔矿区生态系统服务价值的空间分布呈现南北高、中部低的特征。（5）平朔矿区草地、建设用地和林地的生态贡献度分别是-41.52%、-34.49%和-10.09%，三者是主要的贡献因子和敏感因子。
Subjects: Geosciences >> Geography submitted time 2024-01-07 Cooperative journals: 《干旱区地理》
Abstract：黄土高原是我国气候变化敏感区，研究该区相对湿度（RH）时空演变及其与地理因子、气象要素之间的关系，有利于全面了解黄土高原气候变化规律。基于黄土高原及其周边地区90个气象站点逐日RH 观测资料，利用趋势分析、敏感性分析和空间插值等方法，分析了19602021年及生态工程实施前后RH变化特征。结果表明：（1）时间上，黄土高原地区年均RH为57.66%，以-0.376%(10a)-1 速率显著减少（P-1 ，冬季最少 -0.194%(10a)-1 。（2）空间上，黄土高原年及春夏秋季平均RH皆呈自南向北逐渐降低，而冬季表现为南部最高、中北部自东向西逐渐降低；年均及四季平均RH变化趋势空间态势各异。（3）在黄土高原生态工程实施后，年及春夏冬季平均RH不同程度减少，年及夏冬季的趋势变化皆由增大转为减少；所有时序RH均值及趋势变化的空间特征存在较大差异，最典型的趋势变化组合类型是一致偏低型。（4）引起黄土高原年均RH长期变化的主要季节因素是春季，空间上则主要是春季主导型、春夏季组合主导型。（5）黄土高原年均及四季平均RH与纬度呈极显著负相关（P<0.01），与降水量呈极显著正相关（P<0.01），夏季平均RH受各地理因子的协同作用最为明显；年及春夏季平均RH对平均气温最为敏感，秋冬季对风速最为敏感。
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： The Loess Plateau is an important ecological barrier in China. In the context of global change, the carbon balance of the region is of great concern. In this study, based on MOD17A3HGF data, we analyzed the carbon source/sink characteristics of the local area of the Loess Plateau from 2000 to 2020 using the geostatistical model of soil respiration (GSMSR) model, trend analysis, difference analysis, and Geodetector, to reveal the spatial and temporal patterns of the region’s net ecosystem productivity (NEP) and its driving factors from 2000 to 2020. Meanwhile, the study area was divided longitudinally into three subregions, west, center, and east, to compare the variability of drivers within different regions. The results showed that: (1) 49.69% of the localized area of the Loess Plateau shifted from a carbon source to a carbon sink within 21 years. NEP fluctuated upward with time, and was higher in the southeast than in the northwest, with a multi-year average of 12 g C·m−2·a−1· (2) Moisture condition was the main natural factor affecting the spatial distribution of NEP, while land use type was the main anthropogenic factor influencing the spatial distribution of NEP. In addition, the influence of the interaction between different factors on NEP was generally greater than that of single factors. The effects of interactions between different factors on NEP were generally greater than those of individual factors. (3) The factors driving NEP in the three subregions of west, central, and east have clear spatial differentiation characteristics, the central and western regions are more affected by climate, with precipitation, humidity, and other moisture conditions as the main ones. The eastern region is affected by a combination of factors such as topography, climate, and human activities, and anthropogenic interference, represented by land use type, is the strongest among these factors. This knowledge can serve as a basis for effective carbon management strategies and ecosystem conservation efforts in the region.
Subjects: Geosciences >> Geography submitted time 2023-12-06 Cooperative journals: 《干旱区地理》
Abstract：淤地坝对于防治黄土高原水土流失有不可替代的作用，因此精确提取淤地范围和淤地坝点位对研究黄土高原水土有重要意义。现有图像分类方法中缺乏对淤地坝地形特征的考虑，容易被误判为梯田或土堆。除此之外，自动提取研究多集中于淤地范围提取，淤地坝点位仍依赖人工判读。因此，提出一种自动提取淤地坝系的方法：通过深度学习融合面向对象的影像分析（OBIA）方法提取韭园沟流域淤地范围，再利用水文分析方法提取淤地坝点位。结果表明：本方法提取的淤地范围精准率、召回率、F1Score分别为81.97%、90.94%、89.70%，F1Score与仅使用OBIA方法相比提升了21.94%。淤地坝点位的自动识别准确率为81.08%，完整率为88.89%，与前人目视解译的准确度相近，并实现了淤地坝范围和淤地坝点位的全要素提取。研究结果可为黄土高原淤地坝空间布局优化和水土流失评估等分析提供重要基础数据。
Subjects: Geosciences >> Geography submitted time 2023-12-06 Cooperative journals: 《干旱区地理》
Abstract：在多源数据的支撑下，基于敏感性-恢复力-压力模型构建评估指标体系，分析生态恢复工程实施前后（1997年和2021年）陕北黄土高原不同行政区、不同生态功能区和不同坡度的生态脆弱性时空分异规律及驱动机制。结果表明：（1） 陕北黄土高原生态脆弱性明显改善，生态脆弱性指数均值从41.74下降至32.96，减幅21.0%；生态脆弱性等级也整体下降，已由中脆弱和低脆弱性占主导转化为低脆弱性占主导的格局。生态脆弱性存在明显地带性分布特征，从南到北生态脆弱性等级逐步提高。（2） 19972021年，51.2%的区域生态脆弱性有所改善，以中脆弱改善到低脆弱为主；4.6%的区域生态脆弱性有所增加，以一般脆弱增加至低脆弱、低脆弱增加至中脆弱为主。铜川市、延安市和榆林市辖区内生态脆弱性指数和等级均在下降，其中铜川市生态脆弱性最低，榆林市最高。3个生态功能区生态脆弱性指数和等级均在显著下降，降幅表现为：退耕还林区>风沙区>黄桥林区。（3） 符合退耕条件的区域，高等级脆弱性大幅转化为低等级脆弱性，生态脆弱性得到明显改善，工程取得了较为显著的成效。（4） 剖析驱动机制可以发现，人为因素和自然因素的驱动力各占83.1%和16.9%，说明生态恢复工程是区域生态脆弱性显著改善的主要驱动力。研究结果可为该区域生态恢复工程成效评估和生态可持续性修复提供科学的参考数据。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： The ecological protection and high-quality development of the Yellow River Basin has been prioritized as a national strategy. The release and implementation of the Outline of the Yellow River Basin’ s Ecological Protection and High-quality Development Plan in 2021 have placed the Loess Plateau, located in the middle reach of the Yellow River, in a critical phase characterized by the need to sustain ecological restoration achievements while fostering socioeconomic progress. This study provides a comprehensive overview of the current conditions and issues related to ecological construction and socioeconomic development in the Loess Plateau. It proposes four specific suggestions focusing on improving ecosystem stability and sustainability, promoting a green transition in socioeconomic development, implementing scientific territorial planning, and adopting an integrated and coordinated approach to managing the entire Yellow River Basin during ecological restoration efforts. The study aims to provide scientific support for the ecological protection and high-quality development of both the Loess Plateau and the Yellow River Basin.
Subjects: Geosciences >> Geography submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： The Wuding River Basin is the key area for the implementation of the grain for green program on the Loess Plateau. Exploring the spatial differentiation mechanism of land cover and the characteristics of variation of related water-carbon variables is essential for supporting water and soil resources conservation and planning, along with serving the construction of regional ecological civilization. Here we used the linear tendency method, Mann-Kendall trend test, Pettitt test, and geodetector to analyze the spatiotemporal characteristics and the factors driving the spatial differentiation of land cover in Wudinghe River Basin. In addition, from the perspective of land- water- carbon coupling, we analyzed the characteristics of variation of total primary productivity (GPP), actual evapotranspiration (ET), and water use efficiency (WUE). Three main results were as follows: (i) The total grassland, forest, and construction land increased significantly, while the cropland and barren land decreased significantly during 1990-2019. The area of forest and grassland increased mainly in the lower reaches of the basin and along Wuding River. (ii) Population density, precipitation, and temperature have a significant impact on the spatial pattern of land cover. On the whole, the influence of socioeconomic factors is greater than that of natural factors, but the influence of natural factors represented by precipitation and temperature is increasing. (iii) There is a good correlation between the variation of water- carbon variables and land cover change. Spatially, GPP, ET, and WUE are relatively high in the southeastern part of the basin where cropland, forest, and grassland are the main cover, while they are lower in the northwestern part of the basin where grassland and barren land are the main cover. In terms of time, GPP, ET, and WUE all showed increasing trends during 2001-2019. GPP and WUE increased significantly in most parts of the basin, while ET increased significantly mainly in its middle and lower reaches. In conclusion, under the implementation of the grain for green program and climate change, the forest and grass in Wudinghe River Basin have been restored and the ecology has been improved.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-04-07 Cooperative journals: 《干旱区地理》
Abstract： Flash drought is a type of drought characterized by rapid intensification. In the context of global warming, flash droughts are increasingly frequent, which has had a devastating impact on the agricultural ecosystem and public health of China. Understanding the spatiotemporal variation characteristics and influencing factors of flash drought events is of critical importance for monitoring, early warning, and loss prevention. On the basis of ERA5- Land data from 1981 to 2020, this study examined the spatiotemporal variation of two types of flash drought (heat wave and precipitation deficit flash drought) in the Loess Plateau using trend and correlation analyses. The relationship between the different atmosphere-ocean oscillation indices and the number of flash drought is also examined. The following results are presented. (1) The frequency of the two types of flash drought increased significantly from 1981 to 2020, with a higher increasing precipitation deficit rate [0.54 penta·(10a) − 1 ] than that of heat wave [0.46 penta·(10a)−1 ] flash drought. Particularly, the two types of flash drought had a similar pattern in decadal variation. Before 1998, the two types of flash drought primarily displayed low fluctuation. From 1998 to 2010, the number of flash droughts rapidly increased. The growth rate of flash droughts stalled and began to decline after 2010. (2) A spatially significant (P<0.05) upward trend for heat wave (precipitation deficit) flash drought was observed in 36.5% (37.5% ) of the Loess Plateau. The parts of the Loess Plateau with gullies and hills, as well as the eastern Hetao Plain and the Fenwei River Valley Plain, had a marked increase in the incidence of heat waves and precipitation deficit flash droughts. (3) Considering the influencing factors, the trend and interannual oscillations of flash drought in the Loess Plateau can be explained by the sea surface temperature (SST) anomaly in the NINO B region and the atmospheric pressure anomaly in the northern Qinghai-Tibet Plateau. The Loess Plateau had an increase in the probability of flash drought due to positive air pressure anomalies in the northern Qinghai-Tibet Plateau and large SST anomalies in the central equatorial India Ocean.
Subjects: Geosciences >> Geography submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： The accurate estimation of grassland net primary productivity (NPP) is crucial to understanding the carbon cycle of grassland ecosystems and their adaption to climate change. Based on 1788 grassland biomass data and 19 environmental factors (climate, vegetation, soil, and topographic factors), we simulated the spatiotemporal dynamics of grassland NPP in the Loess Plateau from 2002 to 2020 using the random forest (RF) model. The future trends of grassland NPP under four future climate scenarios of shared socioeconomic pathways were estimated. Results showed that (1) the RF model had a good accuracy, which indicated that RF can be used to estimate grassland NPP in the Loess Plateau; (2) grassland NPP in the Loess Plateau exhibited a“high in southeastern and low in northwestern”pattern, with a mean value of 276.55 g C·m−2·a−1. The highest grassland NPP was observed in Guanzhong Plain of Shaanxi; (3) the grassland NPP in the Loess Plateau showed an overall increasing trend during 2002-2020. Regions experiencing an increase in grassland NPP accounted for 55.01% of the total land area, which is mainly located in Guanzhong Plain, western Gansu, and northern Shanxi; (4) under the wetter and warmer climate, grassland NPP in the Loess Plateau will continually increase by the end of this century. Grassland NPP will increase the most under the SSP585 scenario and the least under the SSP126 scenario. RF can be used to simulate the temporal and spatial trends of grassland NPP in the Loess Plateau. The results provide data support for the protection and sustainable development of grassland ecosystem in the Loess Plateau.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
In China, the county is not only an important contributor to carbon emissions and a major carbon sink zone but also a key administrative unit for the implementation of China’s national goals for carbon peak and carbon neutrality. Focusing on Qingcheng County as a typical county in the Loess Plateau, we investigate the carbon emission characteristics and spatiotemporal patterns, to raise awareness of the need for ecological protection of the Yellow River Basin, while achieving high- quality development and green and low carbon transformation. The key results of our study are as follows. (1) The change and structure of county carbon emission in underdeveloped areas have distinct characteristics. Industries below the designated size are the largest source of carbon emissions in Qingcheng County, having a low proportion of industrial carbon emissions but a relatively high proportion of service sector and household carbon emissions. (2) The spatial distribution of carbon emissions in Qingcheng County conforms to the Pareto Principle: 80% of carbon emissions are concentrated in 20% of the region, which is characterized by“overall dispersion and local agglomeration”. The high carbon zones are mainly concentrated in the valley, broken plateau area, and urban area. The medium carbon zones are mainly distributed in the broken plateau area and along the traffic line. Low carbon zones are widely distributed in ridge, hill, and gully areas. (3) The county carbon emissions in the Loess Plateau show clear temporal and spatial pattern differences that are affected by differences in topography. The largest patch index of medium and high carbon zones, such as urban areas, industrial zones, and major towns, increases, the integrity improves, the diversity of carbon sources decreases, and the types tend to be single. The carbon source diversity increases and the aggregation degree decreases in the ecotone between medium carbon zones and low carbon zones, such as transportation lines and residential areas.
Hits
Hits
Downloads
Comment
YES