Water sources of plants and groundwater in typical ecosystems in the lower reaches of the Heihe River Basin

Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.

Tree-ring-based reconstruction of temperature variability(1445–2011) for the upper reaches of the Heihe River Basin, Northwest China

Long-term temperature variability has significant effects on runoff into the upper reaches of inland rivers. This paper developed a tree-ring chronology of Qilian juniper (Sabina przewalskii Kom.) from the upper tree-line of the middle Qilian Mountains within the upper reaches of Heihe River Basin, Northwest China for a long-term reconstruction of temperature at the study site. In this paper, tree-ring chronology was used to examine climate-growth associations considering local climate data obtained from Qilian Meteorological Station. The results showed that temperatures correlated extremely well with standardized growth indices of trees (r=0.564, P<0.001). Tree-ring chronology was highest correlated with annual mean temperature (r=0.641, P<0.0001). Annual mean temperature which spans the period of 1445–2011 was reconstructed and explained 57.8% of the inter-annual to decadal temperature variance at the regional scale for the period 1961–2011. Spatial correlation patterns revealed that reconstructed temperature data and gridded temperature data had a significant correlation on a regional scale, indicating that the reconstruction represents climatic variations for an extended area surrounding the sampling sites. Analysis of the temperature reconstruction indicated that major cold periods occurred during the periods of 1450s–1480s, 1590s–1770s, 1810s–1890s, 1920s–1940s, and 1960s–1970s. Warm intervals occurred during 1490s–1580s, 1780s–1800s, 1900s–1910s, 1950s, and 1980s to present. The coldest 100-year and decadal periods occurred from 1490s–1580s and 1780s–1800s, respectively, while the warmest 100 years within the studied time period was the 20th century. Colder events and intervals coincided with wet or moist conditions in and near the study region. The reconstructed temperature agreed well with other temperature series reconstructed across the surrounding areas, demonstrating that this reconstructed temperature could be used to evaluate regional climate change. Compared to the tree-ring reconstructed temperature from nearby regions and records of glacier fluctuations from the surrounding high mountains, this reconstruction was reliable, and could aid in the evaluation of regional climate variability. Spectral analyses suggested that the reconstructed annual mean temperature variation may be related to large-scale atmospheric–oceanic variability such as the solar activity, Pacific Decadal Oscillation (PDO) and El Ni?o–Southern Oscillation (ENSO).

LAND DESERTIFICATION(DEGRADATION) AND ITS CONTROL IN LOWER REACH REGION OF HEIHE RIVER

The lower reach of Heihe River, also known as Ejina River, was called Ruoshui Riverin ancient times. This area, although fallen into extremely arid temperate desert in the EjinaBanner, Inner Mongolia, has been a main line of communication since then and formed thefertile Ejina Oasis relying on the water source flowing from the Qilian mountains. However,in the recent years the land desertification (degradation) in this area has developed rapidly,

2022年夏季热带印度洋-太平洋海温异常对长江中下游高温异常的影响

利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江中下游地区的温度异常为1.52℃、为近40年来最高,温度正异常的极大值位于河南和湖北两省交界处的西侧。热带印度洋和太平洋海温异常引起了长江中下游约0.39℃的增温,对长江中下游地区此次高温异常的贡献为25.66%。La Ni a事件和负位相IOD事件可通过增强西太平洋副热带高压,进而有利于维持长江中下游地区的异常下沉运动,为高温事件的发生提供了有利条件。

Characteristics of dry-wet abrupt alternation events in the middle and lower reaches of the Yangtze River Basin and the relationship with ENSO

During recent decades, more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities, which have sig- nificant implications on water and food security. To better identify the characteristics of flood-drought alternations, we proposed a modified dry-wet abrupt alternation index （DWAAI） and applied the new method in the middle and lower reaches of the Yangtze River Basin （YRB-ML） to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alterna- tion （DWAA） events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015. We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960. In particular, the DWAA events mainly occurred in May and June in the northwest of the YRB-ML, including Hanjiang River Basin, the middle reaches of the YRB, north of Dongting Lake and northwest of Poyang Lake. In addition, we also analyzed the impact of El Nifio Southern Oscillation （ENSO） on DWAA events in the YRB-ML. The results showed that around 41.04% of DWAA events occurred during the declining stages of La Nifia or within the subsequent 8 months after La Nina, which implies that La Nina events could be predictive signals of DWAA events. Besides, significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events, particularly for the Poyang Lake watershed and the middle reaches of the YRB. This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.

Zircon U-Pb dating and Lu-Hf isotope study of intermediate-mafic sub-volcanic and intrusive rocks in the Lishui Basin in the middle and lower reaches of Yangtze River

Eight Mesozoic sub-volcanic and intrusive rocks in the Lishui Basin have been selected for zircon U-Pb dating and Lu-Hf isotopic analysis. The Laohutou, Datongshan,Daweizhuang, Yeshanao, Yanwaqiao, Xibeishan, Changshantou and Jianshan porphyrites yield concordant early Cretaceous ages of 130.5 ± 1.6 Ma, 136.0 ± 3.4 Ma, 132.7 ±2.7 Ma, 127.0 ± 1.9 Ma, 129.4 ± 1.7 Ma, 133.2 ± 2.1 Ma,131.1 ± 2.3 Ma and 127.4 ± 1.8 Ma, respectively. Zircon eHf(t) values for these rocks range from-3.54 to-9.11, mostly between-3.54 and-5.93, suggesting sources similar to those for coeval igneous rocks in other volcanic basins along the middle and lower reaches of Yangtze River. Considering the geochemical characteristics of coeval magmatic rocks in the middle and lower reaches of Yangtze River and its adjacent areas, this paper proposes a model of slab rollback to explain the Mesozoic magmatism in the east-central part of China continent. In the middle-late Jurassic to early Cretaceous(170–135 Ma), the Pacific plate started to subduct beneath the Eurasian continent, producing a compressive tectonic setting,and magmatism progressed from coast to the inland. The magmas of this period were derived mostly from partial melting of ancient crust. After *135 Ma, the subduction weakened, and the rollback of the subducted Pacific plate produced an extensional environment. This led to the formation of volcanic basins, the partial melting of enriched mantle sources and less ancient crust, and the intrusion of voluminous intermediate-mafic igneous rocks.

长江中下游降雨侵蚀力时空变化及其与植被覆盖的关系

充分掌握大尺度流域降雨侵蚀力的时空变化特征对流域水土保持、防洪减灾和生态环境保护至关重要。基于长江中下游的119个气象站点57a逐日降雨资料,通过Xie模型计算各站降雨侵蚀力,使用旋转经验正交函数(REOF)法对降雨侵蚀力进行区域划分;结合Mann-Kendal检验、重标极差(R/S)法和相关性分析方法分析长江中下游降雨侵蚀力的时空变化特征,并揭示其与植被覆盖度之间的关系。结果表明:(1)长江中下游降雨侵蚀力整体呈上升趋势,年均降雨侵蚀力为5643MJ mm hm^(-2)h^(-1)。(2)不同季节降雨侵蚀力空间分布存在差异。冷季降雨侵蚀力空间分布不均,高值区主要集中在流域的西部和东北部,而暖季降雨侵蚀力则表现为以江西省为中心沿西北方向递减的空间分布格局,最大值和最小值出现在鄱阳湖环湖区(III区)和长江干流武汉以下段及太湖水系(IV区)。(3)长江中下游相邻地理分区间降雨侵蚀力变化速率差异较大,降雨侵蚀力区域性差异显著。其中III区、湘江及赣江流域(I区)和IV区年均降雨侵蚀力呈显著增长趋势(P<0.05)且未来将保持该趋势,为水土保持重点关注区域。(4)研究所发现的长江中下游水土保持重点关注区域的降雨侵蚀力与植被覆盖度存在负相关。但值得注意的是I区在冷季呈现正相关,而且其中的湘江上游流域出现显著正相关。研究表明降雨侵蚀力是影响地表侵蚀过程的关键因素,侵蚀性降水会影响植被覆盖情况,进而影响地表的侵蚀过程。因此在重点关注高降雨侵蚀力地区的同时还需加强植被保护工作。研究结果可为长江中下游区域水土保持及生态环境保护工作提供科学依据。

甘肃省黑河下游河水漫溢的时空演变及其影响因素

生态输水是干旱区内陆河流域退化生态系统恢复的主要措施,而流域下游的河水漫溢直接关系到绿洲的恢复成效。基于1987—2021年全球地表水体数据集,结合流域内自然环境和人类活动等数据,通过GEE平台构建的水体频率,即像素点在特定时间段内观测到水体的次数与总观测次数的比率,分析了黑河下游生态输水前、后河水漫溢的时空演变及其影响因素。结果表明:分水前1987—2001年正义峡、哨马营和狼心山的年均径流量分别为8.86×10^(8)、5.28×10^(8)、4.27×10^(8)m^(3),分水后2002—2021年分别为11.99×10^(8)、8.12×10^(8)、6.70×10^(8)m^(3),狼心山-东居延海段的年均径流量(即绿洲可利用水资源量)为6.17×10^(8)m^(3),时间上主要集中在4—5和9—10月;分水后永久性水体面积逐渐增加且主要集中在东居延海,2004年后东居延海出现永久性水体,水体频率最高出现在哨马营-狼心山段河道两侧,其次是东居延海及其外围区域,东河、西河及西居延海水体频率相对较低;分水前河水漫溢主要是由自然水文过程引起的,同时也受到中游人类活动的较大影响,分水后河水漫溢与生态输水量呈显著正相关(P<0.01),下游年蒸发量和人类活动均与河水漫溢呈显著负相关(P<0.01)。建议兴建和修缮黑河下游水利设施,改善下游河水漫溢的时空分布不均性,保障下游生态系统的健康与安全。

长江中下游流域实际蒸散发演变特征及驱动机制

为了更好地了解长江中下游6个子流域蒸散发量时空演变特征,以及气候和下垫面因子改变对蒸散发量变化的影响,基于GRACE重力卫星观测数据和水量平衡法重建了长江中下游6个子流域实际蒸散发ET序列,评估并融合了3种ET数据集,获得1992—2015年高精度的逐月蒸散发量,分析了6个子流域蒸散发量年值和季节值的变化趋势,引入土地利用程度综合指数La,基于通径分析法定量评估了气候和下垫面因子对各子流域蒸散发量变化的直接和间接影响。结果表明:①3种数据集在长江中下游流域的适用性较好,基于最小二乘权重法的数据融合方法减小了ETrecon与ETNOAH、ETGLEAM的平均差和均方根误差,减小了ETNOAH、ETCR的标准差。②长江中下游流域多年平均蒸散发量为728.7 mm,空间上自西北向东南递增;6个子流域不同季节的蒸散发量均呈升高趋势,其中春、夏季的增幅最大。③各子流域年蒸散发量增加主要由La增强和气温升高所致,气温、La和植被覆盖率等要素的间接作用致使太湖流域风速降低对蒸散发量的影响从正向变为负向。④气温升高促进了NDVI对6个子流域春、夏季蒸散发量增加的正向效应,太湖流域、长江中游和下游干流区秋、冬季降水的增加削弱了辐射降低对蒸散发量变化的作用,而风速上升是洞庭湖流域、中游干流区冬季蒸散发量微弱增加的主导因素。研究结果将为长江中下游流域水资源管理、干旱预测和生态功能评估等研究提供理论基础与科学依据。

“流域-人-歌”三重互联:对长江中下游流域民歌的考察

基于对长江中下游民歌的沿江调查及研究,从“流域-人-歌”三者关系出发,可以发现作为自然区域、作为文化“通道”和“界限”以及作为经济带三种视域下,流域-人-歌三者之间存在互联。随着现代社会经济的发展,传统民歌的存承方式也在发生改变。在国家大力建设长江经济带背景下,应立足于新兴的流域(水域)音乐文化研究,加强对长江流域民歌文化带的保护,进而打造良好的长江经济带文化生态。

东江流域中下游典型土壤分类及养分特征分析——以惠城区为例

以惠城区为例,对东江流域中下游典型土壤进行分类,通过采集1 619个土壤样品进行化验分析,研究东江流域中下游典型土壤养分特征。结果表明,惠城区耕地土壤有机质、全氮含量均属中等偏上水平;青泥格田、花岗岩红泥田等土属有机质含量较高,而乌泥底田、砂页岩赤红地、红色砂页岩赤红地等土属含量较低;青泥格田、花岗岩红泥田、石质土、花岗岩红黄泥田等土属全氮含量较高,而乌泥底田、砂页岩赤红地等土属含量较低;土壤全氮含量与有机质含量之间呈极显著的直线相关关系,回归方程为Y=0.039 8X+0.376 9,相关系数为0.65;有机质、全氮含量累积基本符合不同分类土壤形成规律。土壤碱解氮含量总体上属中等偏上水平,平均含量水平达到三级标准;土壤有效磷含量总体上属上中等水平,平均含量水平达到一级标准;土壤速效钾、缓效钾含量处于中等偏下水平。不同土属类型的土壤碱解氮、有效磷、速效钾、缓效钾含量差异均较明显,没有明显规律可循,主要是受人为施用化肥影响较大。

基于讨赖河中下游流域生态环境保护与可持续发展策略

甘肃位于中国西北内陆地区,其气候特征干旱,降水量稀少,水资源匮乏,处于干旱区的讨赖河流域生态环境十分脆弱。为缓解当前水资源利用中存在的问题,保护生态环境,文章分析了讨赖河中下游流域生态环境的主要问题及成因,提出了相应的治理措施,为该地区生态保护与经济社会可持续发展提供了科学的决策帮助。

黑河流域中游沙荒地元宝枫引种栽培试验研究

元宝枫系一种适应力较强的生态经济型树种。采用客土造林法,在黑河流域中游沙荒地分别栽植陕西杨凌、河南平顶山、山东聊城引进的元宝枫苗木,试验研究表明,1)不同种源的苗木栽植后,栽植成活率最高的是陕西杨凌,为69.3%,分别较山东聊城和河南平顶山高27.2%和32.6%;栽植2年生的元宝枫苗木枝条生长量最大的是陕西杨凌的苗木,枝条平均生长量为108.8cm,分别较山东聊城和河南平顶山枝条平均生长量高16.98%和37.37%;第2年新梢生长量达78.8cm,分别比山东聊城和河南平顶山高34.47%和72.05%;胸径均生长量分别高7.56%和12.04%;2)元宝枫苗木在黑河流域中游沙荒地3月20—25日栽植成活率最高,带土球栽植的较4月20—25日高19.9%,裸根苗高26.3%,胸径生长量均增粗5.81%,新生枝条均生长量提高43.7%;3)带状客土整地后栽植陕西杨凌、河南平顶山和山东聊城的苗木,其成活率分别较局部客土整地提升28.49%、23.61%和25.15%,2年生胸径均生长量增大14.41%、13.57%和14.22%,2年生新生枝条均生长量提高67.9%、43.1%和49.6%。研究成果为元宝枫在黑河流域中游沙荒地引种栽培提供技术支撑。

三河与中国早期王都

司马迁在《史记·货殖列传》中所称“三河”,是指今天流经山西、河南境内的黄河中下游地区。河东位于今山西南部,襄汾陶寺遗址早期约早出夏代一二百年,或当传说中尧、舜、禹时期,陶寺中晚期已在夏代纪年范围之内,此时正是早期国家形成阶段;河内即今太行山东南麓为古黄河所环绕的地区,历史上为商人的主要活动区域;河南指晋、豫两省黄河以南,周公在此营洛邑,即成周与王城,是周人活动的主要区域。河东、河南、河内三个区域既成相对独立区域,又以黄河相连接,为当时“天下之中”“王者所更居”之地。夏、商、周三代王朝的更替与发展壮大都没有离开过古老的黄河流域,从这个角度看,夏、商、周三代中国早期国家的诞生不仅是黄河与黄河文化的馈赠,同时也把中国历史与中华民族的发展推进到了新的阶段。黄河中下游流域龙山时代形成的文化成果为夏、商、周三代早期国家的诞生奠定了坚实的文化基础,成为夏、商、周三代文明的始原。龙山时代之后不久,在黄河中下游地区诞生了中国历史上最早的国家形态和中华民族的雏形——华夏族。

基于降雨情景模拟的长江中下游流域淹没风险

针对长江中下游流域洪涝灾害频发的现状,基于泰森多边形法和河网密度法分别模拟流域降雨和构建子集水区,采用SCS模型和局部等体积法模拟不同降雨重现期下的淹没水深和范围,并以市为单位进行淹没风险的具体分析。结果表明长江中下游流域产流的高值中心集中在水体和城市用地区域,受淹区主要集中在江汉、两湖平原和长江三角洲等低洼区域;随着降雨重现期的增长,遭遇积水的淹没范围越广,陆域的洪涝程度加剧。降雨量与淹没面积近似呈线性关系,当降雨量<80 mm/d,降雨量每增加1 mm,流域的淹没范围增加947 km^(2);当降雨量>80 mm/d时,淹没范围增加644 km^(2)。在以市为单位的具体分析中,武汉市、南京市、南昌市以及孝感市的淹没范围和风险均较高,因而需重点关注与防御。

2010~2020年汉江中下游流域景观格局变化分析

为探究汉江中下游流域景观格局变化的结构特征和驱动因素,基于遥感数据,分析汉江中下游流域2010~2020年土地利用/覆盖变化(LUCC)及景观格局变化,采用支持向量机法,分析土地利用类型时空变化及其景观破碎度、多样性变化和斑块形状等,从不同角度探讨该区域景观格局变化驱动因素。研究结果表明:汉江中下游流域景观格局在自然和人文因素驱动下向着更均衡、更多元化的方向演变,集聚的大型景观类型倾向于被其他景观分割、离散,由单一景观的优势格局演化为更丰富多样的区域景观格局分布;在类别水平上,耕地和草地景观斑块形状破碎化程度增加,城镇建设用地景观形状指数(LSI)和斑块密度(PD)均有不同程度增加。研究结果可为汉江中下游地区的经济发展和生态环境保护提供理论基础。

干旱内陆河流域土地利用转型的生态环境效应变化特征及其驱动因素探测

为探讨土地利用转型对生态环境质量的影响并明确相关驱动因素作用机理,以黑河流域中游这一典型干旱内陆河为研究对象,利用生态环境质量指数、标准差椭圆模型和地理探测器工具,在对研究区2000—2020年土地利用转型生态环境效应数量变化、空间分布及方向特征进行多维测定基础上,对影响生态质量空间分异的驱动因素及其交互作用机制进行了识别与分析。结果表明:(1) 2000—2020年,研究区土地利用转型频发,林地、灌木和人造地表大幅增加,草地、裸地和湿地减少,“南草北裸”的空间分布特征未发生扭转,草地和裸地是流域其他地类最为重要的转型补给源;(2)黑河流域中游生态环境质量整体处于较低水平但向好发展,“北低南高”的空间分布格局显著,其生态环境质量呈“正西北—正东南”朝向的变化趋势特征;(3)人为活动及高程、植被覆盖和坡度是黑河流域生态环境质量空间分异的主要驱动因子,自然、社会和经济诸因素激烈的交互与协同作用,共同导致流域生态环境质量的空间分异。综上,黑河流域中游生态环境质量趋好,但需严控人为活动,保障流域土地利用与生态安全持续稳定。

气候变化和土地利用变化对长江中下游地区植被NPP变化相对贡献分析

基于MODIS数据、气象数据和土地利用类型数据,利用Theil-Sen Median趋势分析、Mann-Kendall显著性检验和重标极差(R/S)分析,揭示长江中下游地区植被生态系统NPP时空演变特征和未来变化趋势;并基于情景设置的相对贡献分析,在区域和格网尺度上定量厘定气候变化和土地利用变化对长江中下游地区植被生态系统NPP变化的相对贡献.结果表明,时间上,2000~2021年长江中下游地区植被NPP整体呈波动上升趋势,上升速率为6.99g/(m^(2)·a).林地、草地和耕地生态系统NPP均呈上升趋势,林地生态系统NPP上升速率最高,为9.79g/(m^(2)·a),草地生态系统NPP上升速率次之,为8.84g/(m^(2)·a),耕地生态系统NPP上升速率最低,为2.34g/(m^(2)·a).空间上,长江中下游地区植被NPP变化斜率呈现“南高北低”的空间分布格局.长江中下游地区整体及各植被生态系统NPP呈上升趋势的面积占比均大于呈下降趋势的面积占比,其中,林地和草地生态系统NPP呈上升趋势的面积占比分别为91.43%和91.48%.长江中下游地区植被NPP未来呈上升趋势的面积占比小于呈下降趋势的面积占比.由相对贡献分析结果可知,区域尺度上,气候变化和土地利用变化对长江中下游地区植被生态系统NPP变化的相对贡献分别为85.60%和10.85%.气候变化主导林地和草地生态系统NPP变化,而土地利用变化主导耕地生态系统NPP变化.格网尺度上,长江中下游地区耕地和草地生态系统NPP变化由土地利用变化主导的面积占比最大,分别为54.99%和56.91%.林地生态系统NPP变化由气候变化主导的面积占比最大,为71.96%.剩余因素对耕地生态系统NPP变化的相对贡献高于林地和草地生态系统.

长江中下游河段低枯水水位流量关系变化规律分析

2022年长江中下游地区发生了夏秋连旱,沙市站水位创历史最低,低枯水水位流量变化引发了生活用水、生产用水、生态用水等系列问题。利用2009~2022年三峡水库试验性蓄水后长江中下游干流实测资料,对沿程各站断面变化、低枯水水位流量关系变化趋势、河道冲淤变化情况进行了分析研究。结果表明:三峡水库试验性蓄水后长江中下游干流各代表站低枯水水位流量关系呈右偏趋势,同流量下水位有不同程度下降,其中沙市站下降幅度最大,宜昌至城陵矶段河道冲刷强度最大。研究成果可为合理调度三峡等长江上游水库,保障中下游生产、生活、生态用水,落实最严格水资源管理、旱情防御等提供重要参考。

汉江中下游水华发展新形势及治理对策分析

随着汉江沿岸经济社会的快速发展以及梯级水利枢纽的相继建成运行,汉江水环境和水动力条件也发生了较大变化,汉江中下游“水华”暴发频率不断增加,给区域水安全保障带来严峻挑战。2022年夏季,在长江流域“汛期反枯”的极端水文条件下,汉江中下游首次发现了蓝藻水华。依托长江流域水质监测中心现有监测站网及时开展了水华应急监测,对监测资料进行了综合分析,结合以往研究成果,初步分析2022年夏季水华成因,提出相应对策及建议。结果表明:①流域水体高营养盐水平仍是本次夏季水华发生的前提条件,高温、强辐射、高pH值是诱发因子,河道水量偏少是外部驱动条件。②汉江水华的时空分布和影响范围有扩大趋势,水体富营养化程度有加重趋势;加强水工程联合运用,改善水动力条件,调节环境容量,是缓减汉江中下游水华问题的最直接途径。③提出了优化综合站网布局、强化全要素动态监测、加强水华基础研究、建立水华防控协同机制等对策建议。