In: Journal of Hydrology and Hydromechanics, vol. 67, no. 3
Lei Gao - Yaji Wang - Josie Geris - Paul Hallett - Xinhua Peng
Detaily:
Rok, strany: 2019, 260 - 270
Kľúčové slová:
Sampling strategy; Subtropical climate; Temporal stability; Vegetation type; Soil moisture prediction.
URL originálneho zdroja: http://www.ih.sav.sk/jhh
O článku:
Subtropical regions have clay-rich, weathered soils, and long dry periods followed by intense rainfall that produces
large fluctuations in soil water content (SWC) and hydrological behavior. This complicates predictions of spatiotemporal
dynamics, as datasets are typically collected at too coarse resolution and observations often represent a duration
that is too short to capture temporal stability. The aim of the present study was to gain further insights into the role of
temporal sampling scale on the observed temporal stability features of SWC order to aid the design of optimal SWC
sampling strategies. This focused on both sampling frequency and total monitoring duration, as previous analyses have
not considered both of these sampling aspects simultaneously. We collected relatively high resolution data of SWC (fortnightly
over 3.5 years) for various soil depths and under contrasting crops (peanuts and citrus) at the red soil region of
southeast China. The dataset was split into a three-year training period and a six-month evaluation period. Altogether 13
sampling frequencies (intervals ranging from 15 to 240 days) and eight monitoring duration periods (between three and
36 months) were derived from the training period to identify temporal stability features and the most time stable location
(MTSL). The prediction accuracies of these MTSLs were tested using the independent evaluation data. Results showed
that vegetation type did affect the spatio-temporal patterns of SWC, whereby the citrus site exhibited a stronger temporal
variation and weaker temporal stability than the peanut site. However, the effects of both sampling frequency and observation
duration were more pronounced, irrespective of the role of vegetation type or soil depth. With increasing sampling
interval or decreasing monitoring duration, temporal stability of SWC was generally overestimated; by less than 10%
when sampling interval increased from every 15 to 240 days and by up to 40% with duration decreasing from 36 to 3
months. Our results suggest that sampling strategies and trade-offs between sampling interval and duration should focus
on capturing the main variability in hydro-climatological conditions. For subtropical conditions, we found that sampling
once every 45 days over 24 months to be the minimum sampling strategy to ensure errors in SWC temporal stability of
less than 10%.
Ako citovať:
ISO 690:
Gao, L., Wang, Y., Geris, J., Hallett, P., Peng, X. 2019. The role of sampling strategy on apparent temporal stability of soil
moisture under subtropical hydroclimatic conditions. In Journal of Hydrology and Hydromechanics, vol. 67, no.3, pp. 260-270. 0042-790X (until 2019) . DOI: https://doi.org/10.2478/johh-2019-0006
APA:
Gao, L., Wang, Y., Geris, J., Hallett, P., Peng, X. (2019). The role of sampling strategy on apparent temporal stability of soil
moisture under subtropical hydroclimatic conditions. Journal of Hydrology and Hydromechanics, 67(3), 260-270. 0042-790X (until 2019) . DOI: https://doi.org/10.2478/johh-2019-0006
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