Snowfall is the dominant form of precipitation in high mountainous areas and its driving melt water has an indispensable role in the hydrological cycle and groundwater recharge, particularly in karstic landscapes with high infiltration capacity. Monitoring snow cover area (SCA) and its melting process is essential for the investigation of climatic variables, hydrology, hydrogeology, and water resource management. Prodigious advances of satellite imaginary technology in the past decades made it possible to monitor spatiotemporal distribution of snow and its melting process. In this research, SCA was investigated using cloud-free images of Landsat-8 from December 2014 to June 2016 and Sentinel-2 from November 2015 to June 2016 at Lasem area (north of Iran) by normalized difference snow index. Simultaneously, the discharges of the main karstic springs were monitored over May 2015 to June 2016. The catchment subdivided into three sub-zones based on the hydrogeological characteristics and snow melting time. Fractional SCA time series within each subdomain used to develop snow melting curve in each subzone. Comparison of melting peaks between the 2014–2015 and 2015–2016 water years shows that melting shifted in average 20 days later in 2016 at north-facing subdomains. North-facing slopes show quite fast transmitting time (20–35 days) of the peak snowmelt to the springs, while the south-facing springs are more silent to the recharge pulses (70–80 days), indicating a higher degree of karstification in north-facing domains. More concentrated snowmelt in 2016 led to increasing peak flow by an average of 15% in the springs fed by north-facing domains.

中文翻译：

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通过遥感监测积雪并评估融水对岩溶泉水排放的影响（Lasem 地区的案例研究）

降雪是高山地区降水的主要形式，其驱动融水对水文循环和地下水补给具有不可或缺的作用，尤其是在具有高渗透能力的岩溶景观中。监测积雪面积 (SCA) 及其融化过程对于气候变量、水文、水文地质和水资源管理的调查至关重要。过去几十年卫星想象技术的巨大进步使得监测雪的时空分布及其融化过程成为可能。在这项研究中，使用归一化差异雪指数在 Lasem 地区（伊朗北部）使用 Landsat-8 2014 年 12 月至 2016 年 6 月和 Sentinel-2 2015 年 11 月至 2016 年 6 月的无云图像对 SCA 进行了调查。同时地，2015 年 5 月至 2016 年 6 月监测了主要岩溶泉的流量。根据水文地质特征和融雪时间将流域细分为三个分区。每个子域内的分数 SCA 时间序列用于开发每个子区域的融雪曲线。比较 2014-2015 和 2015-2016 水年之间的融化峰值表明，2016 年朝北子域的融化平均晚了 20 天。朝北的山坡显示，融雪高峰到泉水的传输时间非常快（20-35 天），而朝南的山坡对补给脉冲（70-80 天）则更安静，表明该地区的岩溶程度较高。朝北的域。2016 年更集中的融雪导致由朝北区域供水的泉水的峰值流量平均增加了 15%。