Temporal and spatial responses of ecological resilience to climate change and human activities in the economic belt on the northern slope of the Tianshan Mountains, China

In the Anthropocene era,human activities have become increasingly complex and diversified.The natural ecosystems need higher ecological resilience to ensure regional sustainable development due to rapid urbanization and industrialization as well as other intensified human activities,especially in arid and semi-arid areas.In the study,we chose the economic belt on the northern slope of the Tianshan Mountains(EBNSTM)in Xinjiang Uygur Autonomous Region of China as a case study.By collecting geographic data and statistical data from 2010 and 2020,we constructed an ecological resilience assessment model based on the ecosystem habitat quality(EHQ),ecosystem landscape stability(ELS),and ecosystem service value(ESV).Further,we analyzed the temporal and spatial variation characteristics of ecological resilience in the EBNSTM from 2010 to 2020 by spatial autocorrelation analysis,and explored its responses to climate change and human activities using the geographically weighted regression(GWR)model.The results showed that the ecological resilience of the EBNSTM was at a low level and increased from 0.2732 to 0.2773 during 2010–2020.The spatial autocorrelation analysis of ecological resilience exhibited a spatial heterogeneity characteristic of"high in the western region and low in the eastern region",and the spatial clustering trend was enhanced during the study period.Desert,Gobi and rapidly urbanized areas showed low level of ecological resilience,and oasis and mountain areas exhibited high level of ecological resilience.Climate factors had an important impact on ecological resilience.Specifically,average annual temperature and annual precipitation were the key climate factors that improved ecological resilience,while average annual evapotranspiration was the main factor that blocked ecological resilience.Among the human activity factors,the distance from the main road showed a negative correlation with ecological resilience.Both night light index and PM2.5 concentration were negatively correlated with ecological resilience in the areas with better ecological conditions,whereas in the areas with poorer ecological conditions,the correlations were positive.The research findings could provide a scientific reference for protecting the ecological environment and promoting the harmony and stability of the human-land relationship in arid and semi-arid areas.

Evolution of economic linkage network of the cities and counties on the northern slope of the Tianshan Mountains,China

The exchanges between cities and counties in the northern slope economic belt of Tianshan Mountains(NSEBTM)are increasingly frequent and the economic linkages are increasingly close,but the spatial distribution of economic development and linkages among the cities and counties within NSEBTM is uneven.Therefore,it is of great significance to study the evolution of spatial-temporal pattern of the economic linkage network of cities and counties on NSEBTM to promote the coordinated and integrated development of the regional economy on NSEBTM.In this study,we used the modified gravity model and social network analysis method to analyze the spatio-temporal evolution characteristics of the economic linkage network structure of cities and counties on NSEBTM in 2000,2010,and 2020.The results showed that the comprehensive development quality level of cities and counties on NSEBTM increased from 2000 to 2020,its growth rate also increased,and its gap between cities and counties continued expanding.Both the spatial distribution patterns of the comprehensive development quality level of cities and counties on NSEBTM in 2000 and 2010 were presented as“high in the middle and low at both ends”,while the spatial distribution pattern of 2020 was exhibited as“high value and low value staggered”.The total amount of external economic linkages of cities and counties on NSEBTM showed an obvious upward trend,and its gap between cities and counties continued expanding,presenting a pattern of“a strong middle section and weak ends”.The direction of economic linkages of NSEBTM existed obvious central orientation and geographical proximity.The density of economic linkage network of NSEBTM increased from 2000 to 2020,and the structure of economic linkage network changed from single-core structure centered with Urumqi City to multicore structure centered with Urumqi City,Karamay City,Shihezi City,and Changji City,shifting from unbalanced development to balanced development.In the future,we should accelerate the construction of urban agglomeration on NSEBTM,cultivate a modern Urumqi metropolitan area,improve comprehensive development quality of the cities and counties at the eastern and western ends,strengthen the intensity of economic linkages between cities and counties,optimize the economic linkage network,and promote the coordinated and integrated development of regional economy.

Sustainable land-use patterns for arid lands: A case study in the northern slope areas of the Tianshan Mountains

Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains （NSTM） as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oa- sis-and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.

Response of ecosystem service value to land use/cover change in the northern slope economic belt of the Tianshan Mountains, Xinjiang, China

Land use/cover change(LUCC)is becoming more and more frequent and extensive as a result of human activities,and is expected to have a major impact on human welfare by altering ecosystem service value(ESV).In this study,we utilized remote sensing images and statistical data to explore the spatial-temporal changes of land use/cover types and ESV in the northern slope economic belt of the Tianshan Mountains in Xinjiang Uygur Autonomous Region,China from 1975 to 2018.During the study period,LUCC in the study region varied significantly.Except grassland and unused land,all the other land use/cover types(cultivated land,forestland,waterbody,and construction land)increased in areas.From 1975 to 2018,the spatial-temporal variations in ESV were also pronounced.The total ESV decreased by 4.00×10^(8) CNY,which was primarily due to the reductions in the areas of grassland and unused land.Waterbody had a much higher ESV than the other land use/cover types.Ultimately,understanding the impact of LUCC on ESV and the interactions among ESV of different land use/cover types will help improve existing land use policies and provide scientific basis for developing new conservation strategies for ecologically fragile areas.

An analysis of oasis stability in arid areas:a case study in the northern slope areas of the Tianshan Mountains

This paper discusses oasis stability at regional scale with a case study in the northern slope areas of the Tianshan Mountains (NSTM). The results showed certain significant aspects. (1) As long as water resources in the oasis keep stable and their utilization efficiency can be maintained or gradually increased, the primary productivity could be continuously increased and the natural primary productivity keeped relatively stable. In this case, it is considered that the oasis is stable and its sustainable development can be achieved at regional scale. (2) Considering the availability of water resources in the oases, the oases on the alluvial-diluvial fans are highly stable. In the alluvial plain downstream of the groundwater overflowing zones the oases are moderately stable and in the lacustrine deltas or dry lacustrine deltas the oases are lowly stable. (3) Enlargement of oases and the increase of water resources and vegetation coverage in the oasis will certainly enhance the 'cold-island effect' of the oasis and increase the stability of oases.

不同牧压对天山北坡中段山地草甸植物群落特征及植物生活型的影响

【目的】研究天山北坡中段山地草甸植物群落特征在不同牧压条件下的变化,为建立合理放牧利用制度提供理论依据。【方法】通过对庙尔沟乡索尔巴斯陶夏、冬牧场的实际放牧强度和草场植被状况进行调查,选择重度(HG)、中度(MG)、轻度(LG)且具代表性地段的放牧场,设置3个不同牧压监测点,每个监测点设置3个重复。【结果】在不同牧压条件下,植物群落优势种略有差异,群落物种数随着放牧强度的增大而减少。随着牧压增大,禾本科、豆科等优良牧草的重要值下降,而杂类草及醉马草的重要值增大;不同牧压对植被生物量的影响最大,其次是植被的盖度和高度,对频度的影响较小,呈现出植被平均高度、总盖度和生物量随放牧强度增大而降低的趋势;不同放牧时期对山地草甸植被优势种和植物生活型有明显影响,在夏季放牧场中植株矮小、重要值很低的金露梅在冬季放牧场中却株型高大,重要值也极高。【结论】在不同牧压条件下,群落物种组成不同,HG、MG、LG物种数分别为26、22和33种,物种间数目相差明显。重度放牧降低了植物群落的高度、盖度和地上生物量,并增大了杂类草和醉马草的优势。随着放牧强度增大,植物的生活型和重要值发生了改变,这也是植物生长过程中适应环境变化的一种策略。

Fluctuation of Picea timberline and paleoenvironment onthe northern slope of Tian-shan Mountains during the late Holocene

As a good indicator of Holocene climate, the fluctuation of alpine timberline is a synthetical result of impacts of many environmental factors dur-ing geological and historical periods and modern times. As the dominant tree species of mountainous conifer forests on the northern slope of Tianshan Mountains in Xinjiang, the distribution of Picea schrenkiana and its population size are sensitive to climatic change. The typical natural profile of Huashuwozi and the nearby Xiaoxigou archaeologi-cal profile, located in Quanzijie Township, Jimusaer County in Xinjiang, were chosen to analyze and compare the relative high-resolution pollen records, and to measure 14C dating and SEM (scanning elec-tron microscope) microstructure for charcoal frag-ments contained in Xiaoxigou profile’s cultural layers. The results show that in these two profiles, the high percentages of Picea (more than 20% and 35%, re-spectively) appeared in the stratum of the same pe-riod (2000-1300 a BP), which corresponds to the charcoal fragment’s age of Picea schrenkiana con-tained in Xiaoxigou cultural layers. These results convincingly revealed that during the period of 2000-1300 a BP, the timberline for Picea schrenkiana on the northern slope of Tianshan Mountains in Xinjiang declined by about 330m compared with the present.

天山北坡经济带植被覆盖度动态变化研究

为探明天山北坡经济带植被覆盖度时空变化及其原因,本研究基于MODIS13Q1NDVI数据、气象数据、地形数据、人文数据,基于Google Earth Engine(GEE)平台,利用Theil-Sen Median趋势分析、Mann-Kendall显著性检验和稳定性分析方法,探究2000-2020年天山北坡经济带植被覆盖度(FVC)时空变化特征及其影响因子.结果表明:天山北坡经济带的FVC表现为两条平行的高覆盖度带.其中中部地区具有较高的植被覆盖度,而边缘地区的植被覆盖度相对较低.2000~2020年间,天山北坡经济带的FVC在时空上呈轻度变化,约占总变化的70%.植被改善区域主要呈现带状分布,集中在研究区的中部,而植被减少区域主要分布在研究区的南缘.整体上,天山北坡的植被覆盖度呈现出西北至东南的相间分布趋势,并且有逐渐上升的趋势.与东部地区相比,西部地区的植被改善更为明显.2000~2020年间,天山北坡经济带的FVC整体上表现出较高的稳定性和较小的波动,其变异程度介于弱变异和中等变异之间.但是,在克拉玛依市北部、乌鲁木齐市西南部以及研究区南缘的零星地区,FVC存在较强的变异.通过地理探测器模型对天山北坡经济带FVC影响因素的研究表明,人类活动(人口密度、夜间灯光和土地利用类型)是FVC空间分异的主要解释因素.从驱动因素来看,人口密度P值为0.283,对FVC影响最大,夜间灯光P值为0.125,土地利用类型P值为0.179.

1990—2022年天山北坡地区不同开垦年限耕层土壤盐分变化

近年来,随着频繁的土地利用变化和大量耕地的开垦,土壤盐渍化已成为导致天山北坡耕地质量退化、阻碍绿洲农业发展的环境因素。本研究基于翔实的调查数据资料、土壤实测数据和中国土地覆盖数据集(CLCD),比较传统插值模型和随机森林插值模型对耕层土壤(0~30 cm)含盐量插值的优缺点;选取精度最高的定量预测模型对天山北坡地区耕层土壤含盐量定量预测,得到耕层土壤含盐量分布变化特征;以空间换时间,将近30 a新开垦耕地耕层土壤含盐量进行比较,分析开垦年限对土壤含盐量的影响。结果表明:(1)与传统的插值方法相比,随机森林算法能够更准确地预测盐渍化土地的土壤盐分分布情况。(2)天山北坡地区,耕层土壤含盐量存在较大空间异质性,即高海拔地区土体中的盐分会随着径流的淋溶,在低海拔的河流下游尾闾或低洼区靠近沙漠一侧积聚。(3)随着开垦年限的延长,天山北坡地区耕层土壤含盐量总体呈现下降的趋势,且土壤盐渍化程度倾向于聚集在一个中等的水平上,趋向于平衡或“中心化”。本研究增进了对当前耕地盐渍化状况及从原始荒地开垦到耕地后耕层土壤盐分变化历程的理解。这为干旱区备用土地资源的开发、管理和有效利用提供了理论支撑,并为农业的持续发展提供了科学依据。

近60a天山北坡经济带天然径流量时空变化及归因识别

天山北坡经济带地处干旱的亚洲腹地,厘清天然径流量(NR)时空变化及成因对统筹区域发展、维持生态安全至关重要。为此,采用Sen’s斜率估计法、Mann-Kendall趋势检验等分析径流量时空变化,基于Budyko假设的水热耦合平衡方程定量评价降水、潜在蒸散发及下垫面对NR变化的贡献。结果表明:(1)近60a天山北坡经济带NR总体呈显著增加趋势,年变化率0.68mm·a-1。1961—1986年波动较大,1987—2012年波动变小且NR增加明显,2013年后NR显著减少。(2)NR大小与海拔变化在空间上高度叠合,天山北坡经济带西部和南部NR较大,西南部与西北部增长幅度大。(3)NR突变点为1980年与2013年,降水一直是NR变化的主导因素,但下垫面影响不断加大,近60a贡献率从31.5%增至45.5%。(4)2012年前天然径流量主要受降水主导,但不同区域影响不同。2013年,西部、东部与中南部下垫面对径流量的影响已超过降水成为主导因素。研究成果深化了天山北坡经济带NR变化的认识,为天山北坡经济带高质量发展提供科学支撑。

天山北坡城市群人居环境适宜性评价

基于人居环境自然和人文综合要素,构建了人居环境综合适宜性指数(HSCI),以天山北坡城市群为研究区,分析其2022年的空间分异规律。结果表明:(1)天山北坡城市群自然环境的空间适宜性受地形起伏度和温湿指数影响显著,整体为一般适宜区集中连片分布、高度适宜区零星分布在天山北坡山麓地带的绿洲。其中胡杨河市和乌鲁木齐县的自然环境适宜性最好;(2)人文环境的空间适宜性受夜间灯光指数和基础服务指数的影响较大,整体形成以乌鲁木齐市和石河子市为中心的“双核”空间特征,并有向周围递减的趋势;(3)天山北坡城市群人居环境综合适宜性指数最好的地方人口分布最多,充分体现了乌鲁木齐市作为区域极核的地位;(4)人居环境适宜性指数与天山北坡城市群的人口、经济和土地匹配程度不足。高质量和较高质量区土地面积仅占总量的2.62%,经济则占总量的54.69%,人口高达总量的59.06%。说明天山北坡城市群地区人口与经济在适宜性方面具有高度匹配性,但人居适宜性指数较高的土地存在过度集中和利用的情况。

天山北坡经济带经济韧性与生态韧性的时空耦合

如何平衡经济-生态间的关系,以应对外部扰动和冲击,成为促进区域可持续发展的关键。借鉴韧性理论,构建了生态韧性和经济韧性评价指标体系,基于多源数据,利用耦合协调度模型和核密度方法分析了天山北坡经济带经济韧性与生态韧性的时空耦合特征,并探索了各要素对二者耦合协调度的影响。结果发现:①2000—2020年天山北坡经济带经济韧性总体以中等水平为主,呈现天山北坡“中段>西段>南部>东段”的空间分异特征;②生态韧性则总体处于低水平,呈现“西北高东南低”“低值集聚、高值分散”的空间分布特征;③经济韧性和生态韧性一直处于“失调”状态,但逐渐由轻度失调向濒临失调转变,且西段和中段的耦合协调度高于东段和南部;④经济韧性与生态韧性各要素对耦合协调度的影响存在差异,其中经济潜力韧性和生态系统抵抗力对经济韧性和生态韧性耦合协调关系的阻滞作用最强,经济结构韧性和生态系统恢复力对经济韧性和生态韧性耦合协调关系的推动作用最强。通过时空动态分析和关键影响因素的识别,本研究为可持续发展政策提供了综合视角。平衡这两个方面不仅对该地区当前的稳定至关重要,也是确保其在未来挑战中长期生存的关键所在。

天山北坡典型草地施肥阈值及不确定性分析

在全球气候变化的背景下,干旱半干旱区草地作为陆地生态系统中重要且非常脆弱的组分之一,显现出一系列生态问题。探究气候变化及人类活动对于该区草地生态系统净初级生产力(NPP)的影响,对于合理利用自然资源,保持农牧业可持续发展具有重要的意义。施肥作为促进作物生长的一种方式,合理施肥也可以提高退化草地的NPP。基于此,本研究拟以天山北坡沿海拔梯度分布的4种草地类型:高山草甸(AM)、中山森林草甸(MMFM)、低山干草原(LMDG)和平原荒漠草原(PDG)为研究对象,基于反硝化-分解模型(DNDC)分析该区典型草地生态系统净初级生产力对施加不同氮肥的响应,并揭示施肥阈值及最优施肥方式。结果表明:1)适度氮肥添加促进了各个类型草地生态系统NPP的增长,但草地NPP对施肥量的响应存在阈值,且不存在适用于4种草地类型的统一最优施肥方式。LMDG草地生态系统对施氮肥的响应最敏感。2)PDG草地NPP达到最大的施肥方式为一年分两次施加100 kg·hm^(-2)硝酸盐,NPP的最大值为68.72 g C·m^(-2)·a^(-1)。LMDG草地NPP最大的施肥方式为一年分两次施加尿素260 kg·hm^(-2),NPP的最大值为263.28 g C·m^(-2)·a^(-1)。MMFM草地生态系统达到NPP最大的施肥方式为一年一次施尿素80 kg·hm^(-2),NPP的最大值为171.22 g C·m^(-2)·a^(-1)。无水氨作为在AM草地中反应最好的氮肥,以最小的施肥量(60 kg·hm^(-2))达到了NPP的最大值(114.62 g C·m^(-2)·a^(-1))。3)通过蒙特卡洛不确定分析的结果显示,施肥时间对PDG和LMDG的影响更为明显,施肥量波动对LMDG和MMFM的影响较其他两种草地更为明显。

基于MS-PT的天山北坡农业灌溉用水时空格局估算及影响因素分析

基于土壤水分平衡方程和遥感数据,利用改进后基于卫星的Priestley-Taylor算法(MS-PT),估算了2018—2020年天山北坡0.1°×0.1°空间分辨率下的农业灌溉用水量,通过与定额法所得到的估算结果进行对比,并采用通量塔数据对关键结果——蒸散发量进行了验证.结果表明:研究区内灌溉时间主要为每年的4—9月,其中7月份灌溉用水达到峰值,3年平均年灌溉用水量为98.90亿m^(3)/a,与定额法估算的结果(94.58亿m^(3)/a)相近.同时,在乌苏市、沙湾县、玛纳斯县以及呼图壁县等农业较为发达的地区,农业灌溉用水量相对较大.此外,农作物的种植结构及种植面积是影响天山北坡农业灌溉用水量的主要因素.

天山北坡城市群高质量测度与障碍因子诊断研究

通过熵权TOPSIS方法,测度2020年天山北坡城市群高质量发展水平,并采用障碍因子模型和耦合协调模型,判定影响高质量发展的障碍因子和城市内部协调度。结果表明:高质量综合得分排名为乌鲁木齐市>克拉玛依市>石河子市>吐鲁番市>五家渠市>昌吉市>阜康市;影响乌鲁木齐市主要障碍因子是建成区绿化覆盖率、每万人图书馆数量、人均城市道路面积、建成区排水管道密度;其余城市的主要障碍因子是进出口贸易额、城市GDP、每万人专利授予量、参加基本养老保险的人数;乌鲁木齐市属于轻度失调,石河子市、克拉玛依市和昌吉市属于严重失调,吐鲁番市、五家渠市和阜康市属于极度失调。天山北坡城市群高质量发展水平与内部耦合协调水平低且呈非均衡的空间分布格局,未来应充分发挥各市的区位、资源和产业优势,着力补齐短板,注重全方位协调发展,提升发展质量。

天山北坡前山带蒙古沙棘不同集水造林技术的效果评价

【目的】探讨天山北坡前山带蒙古沙棘(Hippophae rhamnoides subsp.mongolica)不同集水造林技术对土壤含水率、造林成活率和保存率及株高的影响,结合造林成本进行效果评价,筛选出最佳的蒙古沙棘造林技术,为该地区的人工造林提供技术参考。【方法】以蒙古沙棘优良品种‘新棘1号’(H.rhamnoides‘xinji1’)为研究对象,通过双因素试验设计,设4个水平沟深度:H0(0 cm)、H1(20 cm)、H2(40 cm)、H3(60 cm)和4个保水措施:W0(裸地)、W1(膨润土)、W2(防草布)、W3(膨润土+防草布)。【结果】水平沟深度、保水措施及二者的交互作用均对土壤含水率、造林成活率和保存率及株高有显著影响;在同一保水措施下,随着水平沟深度增加,各指标越优,但造林成本随之增加;在同一水平沟深度下,整体以W3处理最佳,但造林成本也最高;结合造林成本,通过隶属函数评价法综合评价各集水造林技术的效果,H2W3处理得分最高,H0W0得分最低。【结论】本研究筛选出最佳的蒙古沙棘的造林技术为H2W3(40 cm深度+膨润土+覆防草布)处理。

基于PLUS-InVEST模型的天山北坡生态系统碳储量时空变化与预测

土地利用变化作为影响陆地生态系统碳储量的重要因素,研究两者间的关系对维持区域碳平衡和实现双碳目标具有重要意义。基于第三次新疆综合科学考察背景,分析天山北坡1990年、2000年、2010年、2020年土地利用变化与碳储量的定量关系,结合PLUS和InVEST模型,模拟在历史趋势、水资源保护和经济发展3种情景下2030年区域碳储量的空间格局。结果表明:(1)草地和裸地是天山北坡主要土地覆被类型,1990—2020年耕地、林地、水域、建设用地和湿地面积增加,耕地面积增加最多,其余土地利用类型面积减少,草地减少最多。(2)1990—2020年天山北坡碳储量呈“先升后降”趋势,草地、裸地、耕地和林地间的转化是总碳储量变化的主要成因。(3)3种情景下碳储量均低于2020年水平,经济发展情景减幅最为显著,草地减少、裸地增加是碳损失的主要原因。

天山北坡绿洲乡村聚落空间基因解析及影响机制研究

空间基因蕴含着聚落与环境互动形成的空间信息,在空间特色传承上有着重要作用。由于新疆天山北坡地区聚落在独特的自然环境中形成了互动演化的聚落空间形态,因此以其为研究对象,通过卫星影像图和三维数据采集其中的12个典型聚落样本,在从自然环境、空间片段形态、聚落形态、路网形态和拓扑连接五方面提取空间基因的基础上,构建聚落空间基因图谱,运用因子分析与聚类分析方法,对聚落进行分类,阐释其背后蕴含的环境-空间互动影响模式,并提出保护与改造建议,以期为不同地区乡村聚落空间基因研究提供借鉴,为聚落类型划分、乡村特色保护与发展提供研究思路。

天山北坡区域大气污染特征及冬季重污染成因分析——以石河子市为例

以天山北坡典型代表城市石河子市为例,基于地面常规污染物浓度监测、气象观测、激光雷达观测及中尺度气象模型(WRF)模拟资料,综合分析了气象条件和边界层结构变化对空气质量的影响。结果表明:以石河子市为代表的天山北坡地区空气质量季节性差异显著,PM_(2.5)浓度在冬、夏两季相差最高达11.4倍,且冬季(12月—次年2月)大气污染发生率高达81.2%,重度及以上污染天气占59.1%。冬季污染呈连续“污染季”变化特征,在2020—2021年冬季发生的4次重污染过程中,每次重污染过程持续时间为7~27 d,间隔仅1~3 d,各过程均以PM_(2.5)污染为主导,PM_(2.5)峰值浓度为373~425μg/m^(3),PM_(2.5)/PM_(10)均值为0.82。进入秋冬季后,地面连续低温、高湿的气象条件对PM_(2.5)浓度的增长有显著促进作用,以温度<-3℃和65%<相对湿度<92%为主要影响条件,在该条件下边界层高度的显著降低和连续强逆温引起的近地扩散条件转差,是冬“污染季”形成的根本原因。在2021年1月16—22日重污染过程期间,地面为持续低温、高湿、微/静风状态,重污染生消仅随边界层和逆温条件改变,其中污染累积时段边界层高度较清洁时段降低近5倍,逆温强度超过1.5℃/(100 m),后续由逆温的减退和边界层抬升带来3 d清洁天气。

新疆草地时空动态及其对气候变化的响应——以昌吉回族自治州为例

基于MODIS NPP、EVI遥感影像,采用MVC法、一元线性回归法与Pearson相关分析法,探讨天山北坡昌吉州草地植被时空动态及其对同期气温、降水的响应。结果表明:2000—2020年,草地植被NPP、EVI均为跃动式显著递增,2016年后呈逐年递减;NPP、EVI多年均值为0.095 kg C·m^(-2)、0.186;相较于2000年(NPP=0.077 kg C·m^(-2)、EVI=0.166),2020年NPP(0.099 kg C·m^(-2))、EVI(0.194)分别增长了28.57%、16.87%。草地NPP空间异质性显著增加并呈扩大趋势,EVI空间差异逐年递增,变化范围分别为0.038 kg C·m^(-2)(NPP)、0.059(EVI)。在空间上,NPP、EVI多年平均分布具有差异;总体上,NPP、EVI随海拔升高而增加,但绿洲边缘、古尔班通古特沙漠南缘分布有高位EVI,面积占比65.01%的NPP与21.93%的EVI显著递增。9种草地类型植被NPP、EVI与降水呈显著正相关的面积占比远大于同期气温,不同类型草地对降水的响应具有差异。降水是草地植被的重要影响因子,但高海拔区域的适度增温有益于草地植被生长。