Analysis on the Contribution of Artificial Precipitation Enhancement Amount to Annual Water Resources in Liaoning

Based on the water resource balance,the correlation between both the Liaoning water resource and precipitation and total amount of water resource from 1991 to 2004 was analyzed by assuming Liaoning to be an enclosed region.And the calculation methods were developed to quantitatively determine the increase of rainfall due to artificial precipitation,and consequently ascertain the contribution of artificial rainfall amount to water resources.

Surface runoff processes and sustainable utilization of water resources in Manas River Basin, Xinjiang, China

Water is the important resource to guarantee the existence and development of oases in arid areas. To improve the utilization efficiency of water resources in Manas River Basin, this paper investigated the trends and periods of runoff based on the runoff and climate data for the past 50 years. Subsequently, with the socioeconomic and water resources data, we studied a comprehensive evaluation on the water security in this area. The results indicated that the stream flows in the three hydrological stations of Hongshanzui, Kensiwat and Bajiahu have sig- nificantly increased and undergone abrupt changes, with periods of 18 and 20 years. According to assessment, water security in the Manas River Basin was at an unsafe level in 2008. In criterion layer, the ecological security index and the index of supply-demand situation are both at the relatively secure level; the quantity index and so- cioeconomic index of water resources are at the unsafe level and basic security level, respectively. Therefore, in order to achieve sustainable economic and social development within the Manas River Basin, it is vital to take a series of effective measures to improve the status of water security.

Variations of precipitation characteristics during the period 1960–2014 in the Source Region of the Yellow River,China

Precipitation, a natural feature of weather systems in the Earth, is vitally important for the environment of any region. Under global climate change condition, the characteristics of precipitation have changed as a consequence of enhanced global hydrological cycle. The source region of the Yellow River（SRYR）, locating within the Qinghai-Tibet Plateau, is sensitive to the global climate change due to its complex orography and fragile ecosystem. To understand the precipitation characteristics and its impacts on the environment in the region, we studied the characteristics of rainy days and precipitation amount of different precipitation classes, such as light（0–5 and 5–10 mm）, moderate（10–15, 15–20 and 20–25 mm） and heavy（≥25 mm） rains by analyzing the precipitation data of typical meteorological stations in the SRYR during the period 1961–2014, as well as the trends of persistent rainfall events and drought events. Results showed that annual average precipitation in this area had a non-significant（P〉0.05） increasing trend, and 82.5% of the precipitation occurred from May to September. Rainy days of the 0–5 mm precipitation class significantly decreased, whereas the rainy days of 5–10, 10–15, and 20–25 mm precipitation classes increased and that of ≥25 mm precipitation class decreased insignificantly. The persistent rainfall events of 1-or 2-day and more than 2-day showed an increasing trend, with the 1-or 2-day events being more frequent. Meanwhile, the number of short drought periods（≤10 days） increased while long drought periods（〉10 days） decreased. Since the 0–5 mm precipitation class had a huge impact on the grasslands productivity; the 5–10, 10–15, and 20–25 mm precipitation classes had positive effects on vegetation which rely on the deep soil water through moving nutrients and water into the root zone of these vegetation or through the plant-microbe interactions; the ≥25 mm precipitation class contributed to the floods; and more persistent rainfall events and fewer long drought events inferred positive effects on agriculture. Thus, these results indicate grassland degradation, less risk of floods, and the upgrading impact of climate change on agriculture. This study may provide scientific knowledge for policymakers to sustain the eco-environmental resources in the SYSR.

Analysis on Change Tendency of the Precipitation Resource during Growth Period of the Conventional Crops in Plain Area before Taihang Mountains

[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shijiazhuang meteorological station in recent 51 years, average rainfall dudng growth periods of the 9 kinds of conventional crops was obtained. Precipitation tendency dudng growth periods of the 9 kinds of conventional crops in plain area before Taihang Mountains was analyzed by Mann-Kendall nonparametric test. [ Result] Seen from rainfall during growth pedods of the different crops, rainfall was the least during the growth period of winter wheat, followed by summer corn. Rainfall during growth peri- ods of the cotton, oil plant, vegetable, fruit tree, potato, rice and legumes was more. Under different guaranteed rates, precipitation change also had difference. Rainfall change during growth periods of the wheat and corn was bigger, and rainfall change during growth period of the rice was smaller. Change degree of the precipitation during growth periods of the cotton, oil plant, vegetable, fruit tree and legumes was equivalent, while precipitation change during growth period of the potato was the biggest. Seen from change tendency of the precipitation during growth periods of the different crops, precipitation in the growth period of winter wheat was increasing at a speed of 0.62 mm/a. However, precipitation in growth periods of the other crops had a decreasing tendency. Precipitation in the growth periods of summer corn and legumes decreased at the same speed which was 2.11 mm/a, while precipitation in growth periods of the cotton, oil plant, vegetable, fruit tree, potato and rice decreased insignificantly. [ Con dusion] The study laid foundation for determination of the agricultural irrigation water and provided theoretical reference for regional agricultural water-saving.

Ecological Significance of Developing Cloud Water Resource in Liaoning Province

The potential evapotranspiration of main ecosystems and its relationship with precipitation during the same period were studied,the results showed that precipitation did not meet the water requirement of main ecosystems influencing ecosystem construction.Based on the data from Liaoning Provincial Department of Water Resources and Liaoning Meteorological Archives,the characteristics of water inflow and each component were analyzed,and it showed that the imbalance between supply and demand of water resource in main ecosystems was improved by means of developing cloud water resource to increase atmospheric precipitation.

Trends of Regional Precipitation and Their Control Mechanisms during 1979–2013

Trends in precipitation are critical to water resources. Considerable uncertainty remains concerning the trends of regional precipitation in response to global warming and their controlling mechanisms. Here, we use an interannual difference method to derive trends of regional precipitation from GPCP （Global Precipitation Climatology Project） data and MERRA （Modern- Era Retrospective Analysis for Research and Applications） reanalysis in the near-global domain of 60~ S-60~N during a major global warming period of 1979-2013. We find that trends of regional annual precipitation are primarily driven by changes in the top 30% heavy precipitation events, which in turn are controlled by changes in precipitable water in response to global warming, i.e., by thermodynamic processes. Significant drying trends are found in most parts of the U.S. and eastern Canada, the Middle East, and eastern South America, while significant increases in precipitation occur in northern Australia, southern Africa, western India and western China. In addition, as the climate warms there are extensive enhancements and expansions of the three major tropical precipitation centers-the Maritime Continent, Central America, and tropical Africa-leading to the observed widening of Hadley cells and a significant strengthening of the global hydrological cycle.

Assessing the Precipitation Enhancement Development Potential in 2013 Using the CWRPEP Method in Liaoning Province

Objective] The research aimed to assess the development potential of ar-tificial precipitation in Liaoning Province. [Method] The evaluation method of cloud water resource for precipitation enhancement potential was used. [Result] The annu-al total precipitation enhancement potential by cloud water resource in the air in 2013 was 1.23 bil ion tons in Liaoning, and cloud water resource for precipitation enhancement was 1.63 bil ion tons. [Conclusion] The spatial and temporal distribution for development potential of cloud water resource in the air was very uneven in Liaoning Province, and the mainly period was during spring and autumn. It wil be received obvious effect in the two seasons. In order to compensate for the restric-tion of the operational capability lack on cloud water resource development, we need to continue to improve the operation capacity building.

Effect of Climate Variability and Human Activities on Runoff in the Jinghe River Basin, Northwest China

Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB) in the arid region of northwest China. The nonparametric Mann–Kendall test and the precipitation-runoff double cumulative curve(PRDCC) were used to identify change trend and abrupt change points in the annual runoff. It was found that the runoff in the JRB has periodically fluctuated in the past 56 yr. Abrupt change point in annual runoff was identified in the JRB, which occurred in the years around 1964 and 1996 dividing the long-term hydrologic series into a natural period(1957 – 1964) and a climate and man-induced period(1965 – 1996 and 1997 – 2012). In the 1965 – 1996 period, human activities were the main factor that decreased runoff with contribution of 88.9%, while climate variability only accounted for 11.1%. However,the impact of climate variability has been increased from 11.1% to 47.5% during 1997 – 2012, showing that runoff in JRB is more sensitive to climate variability during global warming. This study distinguishes theeffect of climate variability from human activities on runoff, which can do duty for a reference for regional water resources assessment and management.

2021年10月山西一次罕见持续性强降水过程物理机制分析

利用气象观测资料、NCEP/NCAR 1°×1°×再分析以及GDAS等资料,对2021年10月2—7日山西持续性强降水天气过程进行分析。结果表明:稳定的乌拉尔山低槽后部冷空气扩散,中纬度短波槽东移,与副热带高压外围西南暖湿气流持续交汇,高低空急流耦合形成强烈上升运动,低层切变线和地面辐合线稳定维持,及低层水汽不断输送并形成辐合,为持续性强降水的发生发展提供有利的动力和水汽条件。强降水过程分为对流性降水和稳定性降水2个阶段,2个阶段水汽输送通道的源地、路径、高度存在明显差异,但水汽输送贡献率均为对流层中低层山西南侧的水汽输送占主导地位。降水开始前,对流层中上层存在对称不稳定,大气可降水量明显跃增;对流性降水阶段,干空气不断入侵,对流不稳定快速建立与释放,对流层中低层水汽辐合区与强上升气流配合,导致山西出现强对流天气。地形的阻挡、抬升及地形收缩作用对局地极端强降水有增幅作用。

Characteristics of Cloud Water Resource and Precipitation Efficiency of Hydrometeors over Northwest China

Understanding the characteristics of cloud water resource(CWR)and precipitation efficiency of hydrometeors(PEh)is imperative for the application of CWR in Northwest China.The atmospheric precipitable water(PW)in all four seasons and clouds and PEh in summer were studied with ERA-5 and CloudSat data in this region.The results show that topography,especially in the Tibetan Plateau,exerts significant impacts on the precipitation and PW in summer,since large amounts of clouds are distributed along the mountain ranges.The study region is divided into four typical areas:the monsoon area in eastern Northwest China(NWE),the Qilian Mountains area(QM),the Tianshan Mountains area(TM),and the Source of Three Rivers area(STR).Over the four areas,cloud top height(6.3 km)and cloud base height(3.3 km)over NWE are higher,and precipitating clouds are thicker(7 km)in the single-layer clouds.Liquid water content decreases with increasing altitude,while the ice water content first increases and then decreases.Liquid water path is higher over NWE(0.11 kg m^(−2))than over TM and STR(0.05 kg m^(−2)),and the ice water path is mainly concentrated within the range of 0.025–0.055 kg m^(−2).The PEh values are distributed unevenly and affected evidently by the terrain.Although the PEh values in the four typical areas(0.3–0.6)are higher than those in other regions,the CWR is relatively abundant and has a higher exploitation potential.Therefore,it is well-founded to exploit CWR for alleviating water shortages in these areas of Northwest China in summer.

漓江流域不同水期降水径流突变分析

丰、平、枯不同水期降水径流突变分析对于准确认识漓江水资源变化规律、科学实施水资源调控,具有十分重要的意义。分别选取漓江上中下游的桂林、阳朔、平乐3个水文站1968-2021年降水径流月尺度序列,分析降水径流年内和年际分布;分别对丰、平、枯水期单独采用Mann-Kendall检验法和滑动t检验进行突变分析,结合漓江上游防洪及漓江补水枢纽工程建设运行情况分析突变点及其成因;应用累积量斜率变化率比较法,分析降水和人为活动对径流突变的贡献率。研究结果表明:①漓江流域年降水量上游呈现递增趋势,下游呈现递减趋势;年径流量整体呈现上升趋势。②漓江流域上中下游3个站点在丰、平、枯水期的突变点不一致。③水利工程建设对径流的影响较为明显,尤其是枯水期。

信阳市水资源时空变化特征研究

采用线性回归、滑动T检验、Mann-Kendall检验法和Morlet小波分析法对信阳市1956—2020年降水量、地表水、地下水以及水资源总量的趋势性、突变性以及周期性进行分析。结果表明:(1)1956—2020年信阳市降水量、地下水、地表水、水资源总量总体呈不显著的减少趋势,但突变性和周期性有所差异;降水量在1970年和2017年发生突变,地表水和水资源总量突变点发生在2014年,三者的主导周期均为9a和23a;地下水未发生显著突变,主导周期为15~16a。(2)预计地表水的丰水期会持续到2028年左右;地下水的枯水期持续到2024年后会迎来8年左右的丰水期。(3)降水量呈自南向北递减的空间分布;水资源总量和地表水资源量则均呈现由西向东递增的空间分布特征;地下水资源量呈现由南部向北部递增的趋势。(4)地表水以及水资源总量受降水量的影响显著,地下水与降水量的相关系数最小,分析表明研究区地下水资源量稳定性强。研究结果可为信阳水资源合理配置以及可持续利用提供参考。

珠江三角洲水资源变化特征及承载力分析

以珠江三角洲为研究对象,基于2010—2020年地表水资源量、地下水资源量、降水量等13组数据,分析珠江三角洲各市水资源的时空分布特征,构建水资源承载力综合评价体系,进一步对珠江三角洲水资源承载力进行研究。结果表明:珠江三角洲地表水资源与地下水资源呈现相似的变化趋势;珠江三角洲总用水量呈递减趋势,用水效率不断提高,工业用水和农业用水的空间分布差异较大;珠江三角洲中部地区水资源承载力等级普遍较低,外围地区水资源承载力较高;珠江三角洲地区2010—2020年水资源承载力总体呈现下降趋势,需要政府统筹规划,因地制宜,综合分析水资源各类指标,达到人与水环境和谐统一。

基于GIS的扬州水资源分布与承载力研究

为综合评价经济快速发展区水资源情势,以扬州市为例,应用近5年来GPM卫星降水数据经降尺度后得到区域详细降水资源分布图;另基于开源数据集搜集并确立水资源承载力指标因子,结合熵权法和GIS技术开展水资源承载力空间评价。结果表明,近5年来扬州市降水量介于791 mm~914 mm,呈现自动向西减少格局,总体降水资源丰度较高;区域水资源承载力平均值为0.54,反映了该地水资源供需紧张态势;另外水资源承载力呈斑块状异质性分布,与区域土地利用、人口密度分布一致。

廊坊市北三县地表水资源量分析研究

随着京津冀协同发展,廊坊市北三县经济社会快速发展,用水需求不断增加,水资源供需矛盾日益突出。通过matlab软件编程对北三县1956—2022年近67年降雨量和地表水资源量进行趋势性、周期性和突变性分析,发现降雨量和地表水资源量均呈现明显下降趋势,如果不考虑其他水源,当地水资源供需矛盾会日益突出。研究成果可为当地水资源的合理开发和优化配置提供技术支撑。

1956~2020年天河流域水资源变化特征研究

为了研究天河流域水资源变化情况,采用天河流域十堰境内各雨量站点以及贾家坊水文站1956~2020年实测降水、径流资料,结合流域内6个水生态监测断面逐月的水质监测数据,分析天河流域降水、径流、水质的变化情况,探讨流量对水质的影响。结果表明:天河流域降水有明显的年际变化,季节降水量以夏季最多,春、秋两季次之,冬季最少;除年、春季降水量表现为减少趋势外,其他3个季节的降水量均表现为增加趋势,春季降水量变化率为-5.92 mm/10 a,并且通过了5%显著性检验;年、季降水量UF曲线均没有超过显著性水平线,认为没有明显的突变点。天河流域地表水资源量呈减少趋势,下降速率约2086万m^(3)/10 a,M-K检测值为-3.67,呈显著的下降趋势;根据M-K突变点检验,天河流域地表水资源量在1991年前后发生了突变,产生了明显的下降趋势。利用贾家坊水文站的2015~2020年的实测月平均流量资料与逐月水质监测资料进行对比分析,没有发现水质参数浓度与流量变化之间表现出明显的关系。

新疆降水特征及其对水资源和生态环境的影响

新疆位于欧亚大陆腹地,空中水汽来源少,水资源匮乏,生态环境脆弱,降水有其独特的时空分布特征,且对水资源形成和生态环境有着十分重要的影响和作用.利用全疆106处水文、气象站1956—2005年的降水资料以及相关分析研究成果,从水资源的角度对新疆降水的形成条件、时空分布特征和对水资源、生态环境的影响进行了分析.结果表明:多年平均年降水总量为2 588×108m3,折合降水深157.4 mm;90%以上的站点年降水量变差系数在0.2～0.7之间;连续最大4个月降水量在40%以上,平均降水产流系数为34%.新疆降水的稀少导致了其生态环境的极端脆弱,绿洲面积仅占全疆总面积的9%,而沙漠面积却达全疆的25.7%.未来新疆地区仍然是干旱、半干旱地区,大气降水资源有限,必须通过其它途径来解决新疆水资源短缺问题.

黄河中游水文变化趋势及其对气候变化的响应

黄河中游水资源匮乏,分析水文要素变化趋势对实现水资源的可持续开发利用具有重要意义。根据流域地貌特征及水文站控制情况,将黄河中游划分为3个区间,分别为：河-龙区间、龙-三区间和三-花区间,采用Mann-Kendall秩次相关检验法与线性回归方法,分析检验了各区间年径流量的历史变化趋势。采用设定情景与水文模拟相结合的途径,评估了不同区间河川径流量对气候变化的响应。根据1950-2005年资料分析,结果表明：黄河中游干流控制站实测径流量与区间径流量均具有显著的减少趋势。若气温升高1℃,年径流量将减少3.7%-6.6%;河川径流对降水变化更为敏感,若降水减少10%,河川径流量将减少17%-22%;近些年黄河中游气温升高和降水减少是河川径流减少的重要原因之一。

基于小波分析的地下水水位与降水的周期性特征研究

选取北京西山地区2000-2010年6个第四系承压水长观孔逐月观测水位及气象站降水数据,运用连续小波变换方法,对降水量和地下水水位的多时间尺度变化特征进行分析,并采用交叉小波变换探讨了二者关系.结果表明：1）北京西山地区降水具有9～16个月的主振荡周期,持续时间较长,不同季节的多周期特征明显;2）承压水水位存在12个月左右的振荡周期,但持续时间较短,且各观测孔水位周期性特征差异较大;3）交叉小波变换结果表明该地区降水量和承压水水位具有显著的共振关系,地下水水位峰值出现时间一般滞后降水峰值约5～7个月.

华北地区降水量的小波分析

由于华北各地区受气候影响不同 ,不同地区的降雨变化也有很大差异 ,因此为全面分析华北地区的未来水资源量的变化趋势 ,本文将华北地区划分为 6个代表区域 ,利用小波分析方法研究了华北地区降水分布的特征和年代际变化 ,在此基础上 ,对今后几年华北降雨的演变趋势作一初步的探讨和估计。这对掌握华北地区水资源量的演变规律是一个有益的探索。