Data for: Influence of cryosphere outflow and land cover on stream water quality in Central Asia's glacierized catchments

Stream water pH, temperature, electrical conductivity, and nitrate and phosphate concentrations are provided for four catchments (485 – 13 500 km2), all with glaciers and major urban areas in Central Asia. The catchments are: Kaskelen (Kazakhstan), Ala-Archa (Kyrgyzstan), Chirchik (Uzbekistan) and the Kofarnihon (Tajikistan). Measurements were made in stream water, groundwater, reservoir and lake samples over a 22-month period at fortnightly intervals from 35 sites. The water samples were collected at fixed locations along the main channel from 10 – 20 km downstream of the periglacial headwaters to the lowlands, from large tributaries, and from three deep wells, two wells that were artesian, and from three further springs. Sample collection started between April and July 2019 and ended between October 2020 and January 2021 dependent on the country. In addition, data are provided for cryosphere samples. Snow and glacial melt water samples were collected during the summers of 2019, 2020 and 2021 at the Tuyuksu (KZ) glacier, in 2019 and 2020 at the Golubin (KG) glacier, and at the Barkrak and Tekesh glaciers (UZ) in 2020. The snow samples were collected from snow pits using plastic scoops, placed in plastic bags, melted at room temperature, and filtered and stored as the other water samples. The snow pit sampling was most extensive in KZ where, in 2019, samples were collected from 6 cm layers from the top to the bottom of the snow pit. In 2020, the snow pit was divided into three equal vertical layers of the overall depth of 162 cm and one sample was taken from each layer. In Kyrgyzstan, the cryosphere samples (snow, glacial ice and glacial melt) were collected in 2019 and 2020. In Uzbekistan, 13 samples were collected from the Tekesh and Barkrak glaciers in June and July 2020. In Kazakhstan, at least three water samples were collected in immediate proximity of the Tuyuksu glacier terminus. Water samples were also collected from the outflow of Gorodetskiy and Morennyi rock glaciers and the meltwater from the permafrost active layer in the Ulken and Kishi Almaty headwaters. In total, cryosphere samples were taken at 39 unique locations, and the pH, EC and water temperature were measured in situ except were samples required melting, and NO3--N and PO43--P was measured on return to the laboratory. Not all analytes could be measured in every sample. The sampling and analysis methods are described in the publication ‘Influence of cryosphere outflow and land cover on stream water quality in Central Asia's glacierized catchments‘. The R-scripts used to plot the data and run an ANOVA analysis are included.

本数据集提供了中亚4个均发育冰川且存在大型城区的流域（catchment，面积485–13500 km²）的河流水pH值、水温、电导率（electrical conductivity）以及硝酸盐和磷酸盐浓度数据。4个流域分别为：卡斯克连（Kaskelen，哈萨克斯坦）、阿拉阿尔恰（Ala-Archa，吉尔吉斯斯坦）、奇尔奇克（Chirchik，乌兹别克斯坦）以及科法尔尼洪（Kofarnihon，塔吉克斯坦）。
研究于22个月内以每两周一次的频率，在35个采样点采集了河流水、地下水、水库及湖泊水样。采样点位涵盖：冰缘源头下游10–20 km至低地的主河道固定位置、大型支流，以及3口深水井、2口自流井和另外3处泉眼。采样启动时间为2019年4月至7月，结束时间为2020年10月至2021年1月，具体因国家而异。
此外，数据集还包含冰冻圈样品数据。分别于2019、2020和2021年夏季在图尤克苏（Tuyuksu，哈萨克斯坦）冰川采集雪样与冰川融水样品；2019和2020年在戈卢布金（Golubin，吉尔吉斯斯坦）冰川采样；2020年在巴克拉克（Barkrak）与特克什（Tekesh，乌兹别克斯坦）冰川采样。雪样采用塑料铲从雪坑中采集，装入塑料袋后于室温下融化，随后过滤并与其他水样一同保存。哈萨克斯坦的雪坑采样最为全面：2019年按6 cm层厚从雪坑顶部至底部逐层采集样品；2020年将总深度162 cm的雪坑均分为3个垂直层，每层采集1份样品。
吉尔吉斯斯坦于2019和2020年采集了冰冻圈样品（雪、冰川冰及冰川融水）；乌兹别克斯坦于2020年6-7月从特克什和巴克拉克冰川采集了13份样品。哈萨克斯坦在图尤克苏冰川末端附近至少采集了3份水样，同时还采集了戈罗杰茨基（Gorodetskiy）与莫列尼（Morennyi）岩冰川的出水水样，以及乌尔肯（Ulken）和基希阿尔马蒂（Kishi Almaty）源头区多年冻土活动层的融水。
总计在39个独特点位采集了冰冻圈样品。除需预先融化的样品外，其余样品均原位测定了pH值、电导率与水温；硝态氮（NO3--N）与正磷酸盐（PO43--P）则在返回实验室后进行测定。并非所有分析物均可在每份样品中完成检测。
采样与分析方法详见论文《Influence of cryosphere outflow and land cover on stream water quality in Central Asia's glacierized catchments》，本数据集同时附带了用于绘图及方差分析（ANOVA）的R脚本。