Journal of Earth System Science ( IF 1.9 ) Pub Date : 2020-10-20 , DOI: 10.1007/s12040-020-01465-2 Ch Samurembi Chanu , Harika Munagapati , V M Tiwari , Arvind Kumar , L Elango
Abstract
This study integrates the time series of satellite data, i.e. (terrestrial water storage (TWS) extracted from Gravity Recovery and Climate Experiment (GRACE), soil moisture (SM) from Global Land Data Assimilation System (GLDAS), rainfall from Tropical Rainfall Measuring Mission (TRMM)) with in-situ data, i.e. (groundwater (GW) observatory well data and surface water (SW) as reservoir level from Tamil Nadu Public Work Department (TN PWD)) to estimate the water storage of the study area for the period from 2002 March to 2016 December. The study area encompasses three districts of Tamil Nadu State – Chennai, Kancheepuram and Tiruvallur. It was previously observed that the groundwater level in this study area is decreasing at an alarming rate. Trends and residuals of the times series of all the previously stated components were analyzed. Negative trends were observed in the case of ΔSW, ΔSM, ΔGW, ΔTWS-GRACE, but rainfall shows a slight positive trend. Rainfall, being the input for water storage, a marginal increase in rainfall cannot affect the variability of ΔSM, ΔSW, ΔGW and ΔTWS-GRACE. ΔTWS decreases approximately 0.12 cm yr−1 averaged water level equal to a total volume −7.5 km3. The result of this study shows a decrease in the total storage of groundwater in the study area during the study period from 2002 March to 2016 December. Seawater intrusion due to an increase in sea surface height also shows an impact on ΔTWS derived from grace, in the form of anomalously elevated ΔTWS. A good agreement between ∆TWS-GRACE and ∆TWS-in-situ is found except where sea-water intrusion occurs.
Research Highlights
-
Areal extent of the study area is less than the optimum suggested for GRACE related investigation. The amplitude of the GRACE signal is 300 km and it is recommended that the study area to be larger than that. Our study is perhaps the first such attempt where the study area is much less than recommended.
-
We were able to get a good correlation between ∆GWGRACE and ∆GWINSITU despite the challenge of spatial resolution.
-
A significant finding of the investigation is that distinction in estimates of groundwater changes between GRACE estimates and in-situ perception happens in grids which mostly have sea-area or are intensely impact by urbanization related LULC changes.
-
The impact of various precipitation mechanisms in the examination area was contemplated.
中文翻译：
利用GRACE时间序列数据估算小规模地下水
摘要
这项研究整合了卫星数据的时间序列，即（从重力恢复和气候实验（GRACE）提取的地面水存储（TWS），从全球土地数据同化系统（GLDAS）提取的土壤湿度（SM），热带雨量测量任务的降雨） （TRMM））与原位数据，例如（泰米尔纳德邦公共工作部（TN PWD）的地下水（GW）观测井数据和地表水（SW）作为水库水位），以估算2002年3月至2016年12月期间研究区域的储水量。研究区域包括泰米尔纳德邦的三个区–钦奈，北碧府和蒂鲁瓦鲁尔。先前曾观察到该研究区的地下水位以惊人的速度下降。分析了所有前述组件的时间序列的趋势和残差。在的情况下，观察到的不利趋势Δ SW，Δ SM，Δ GW，ΔTWS-GRACE，但降雨量显示出小幅积极的趋势。雨量，是用于储水的输入，在降雨略有增加可以在不影响的可变性Δ SM，Δ SW，Δ GW和Δ TWS-GRACE。Δ TWS减小大约0.12厘米年-1平均水位等于总体积-7.5公里3。这项研究的结果显示，在研究区域2002年3月至2016年12月期间，研究区域的地下水总储量减少了。海水入侵由于增加在海面高度还示出了在发生撞击Δ TWS从宽限期衍生，在异常升高的形式Δ交易平台。在∆ TWS-GRACE和∆ TWS-原位之间找到了很好的协议，除了发生海水入侵的地方。
研究重点
-
研究区域的实际范围小于与GRACE相关的研究建议的最佳范围。GRACE信号的幅度为300 km，建议研究区域大于该范围。我们的研究可能是第一个这样的尝试，其中研究范围比建议的要少得多。
-
尽管空间分辨率面临挑战，我们仍然能够在∆ GWGRACE和∆ GWINSITU之间获得良好的相关性。
-
该调查的一个重要发现是，在GRACE估计值与原位感知之间的地下水变化估计值之间的区别发生在大部分具有海域或受城市化相关LULC变化强烈影响的网格中。
-
考虑了各种降水机制对检查区域的影响。
京公网安备 11010802027423号