DOI: 10.5194/hess-22-6611-2018
论文题名: Developing a drought-monitoring index for the contiguous US using SMAP
作者: Sadri S. ; Wood E.F. ; Pan M.
刊名: Hydrology and Earth System Sciences
ISSN: 1027-5606
出版年: 2018
卷: 22, 期: 12 起始页码: 6611
结束页码: 6626
语种: 英语
Scopus关键词: Drought
; Maps
; Microwave devices
; Microwave measurement
; Moisture control
; NASA
; Passive filters
; Soil moisture
; Dry and wet conditions
; Gravity recovery and climate experiments
; Kolmogorov-Smirnov test
; Microwave radiometers
; Soil moisture active passive (SMAP)
; Soil moisture monitoring
; Standard precipitation indices
; Variable infiltration capacities
; Probability distributions
; drought
; GRACE
; index method
; microwave radiometer
; monitoring system
; rhizosphere
; soil moisture
; New Jersey
; Princeton [New Jersey]
; United States
; United States
英文摘要: Since April 2015, NASA's Soil Moisture Active Passive (SMAP) mission has monitored near-surface soil moisture, mapping the globe (between 85.044° N/S) using an L-band (1.4 GHz) microwave radiometer in 2-3 days depending on location. Of particular interest to SMAP-based agricultural applications is a monitoring product that assesses the SMAP near-surface soil moisture in terms of probability percentiles for dry and wet conditions. However, the short SMAP record length poses a statistical challenge for meaningful assessment of its indices. This study presents initial insights about using SMAP for monitoring drought and pluvial regions with a first application over the contiguous United States (CONUS). SMAP soil moisture data from April 2015 to December 2017 at both near-surface (5 cm) SPL3SMP, or Level 3, at ∼ 36 km resolution, and root-zone SPL4SMAU, or Level 4, at ∼ 9 km resolution, were fitted to beta distributions and were used to construct probability distributions for warm (May-October) and cold (November-April) seasons. To assess the data adequacy and have confidence in using short-term SMAP for a drought index estimate, we analyzed individual grids by defining two filters and a combination of them, which could separate the 5815 grids covering CONUS into passed and failed grids. The two filters were (1) the Kolmogorov-Smirnov (KS) test for beta-fitted long-term and the short-term variable infiltration capacity (VIC) land surface model (LSM) with 95% confidence and (2) good correlation (≥ 0:4) between beta-fitted VIC and beta-fitted SPL3SMP. To evaluate which filter is the best, we defined a mean distance (MD) metric, assuming a VIC index at 36 km resolution as the ground truth. For both warm and cold seasons, the union of the filters - which also gives the best coverage of the grids throughout CONUS - was chosen to be the most reliable filter. We visually compared our SMAP-based drought index maps with metrics such as the U.S. Drought Monitor (from D0-D4), 1-month Standard Precipitation Index (SPI) and near-surface VIC from Princeton University. The root-zone drought index maps were shown to be similar to those produced by the root-zone VIC, 3- month SPI, and the Gravity Recovery and Climate Experiment (GRACE). This study is a step forward towards building a national and international soil moisture monitoring system without which quantitative measures of drought and pluvial conditions will remain difficult to judge. © Author(s) 2018. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163098
Appears in Collections: 气候变化与战略
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作者单位: Sadri, S., Department of Civil and Environmental Engineering, Princeton University, 59 Olden St, Princeton, NJ 08540, United States; Wood, E.F., Department of Civil and Environmental Engineering, Princeton University, 59 Olden St, Princeton, NJ 08540, United States; Pan, M., Department of Civil and Environmental Engineering, Princeton University, 59 Olden St, Princeton, NJ 08540, United States
Recommended Citation:
Sadri S.,Wood E.F.,Pan M.. Developing a drought-monitoring index for the contiguous US using SMAP[J]. Hydrology and Earth System Sciences,2018-01-01,22(12)