Recent trends (2003–2013) of land surface heat fluxes on the southern side of the central Himalayas, Nepal

Amatya, Pukar; Ma, Yaoming; Han, Cunbo; Wang, Binbin; Devkota, Laxmi Prasad

doi:10.1002/2015jd023510

Cited by 12 publications

(6 citation statements)

References 73 publications

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“…G 0 was measured every half‐hour by a soil heat flux plate (SHF) buried at depth of 5 cm under the ground but there are many missing data in the observations. K. Yang and Wang (2008) proposed a method to calculate G 0 from the soil temperature and soil moisture profile data through the thermal diffusion equation and it has been widely used and verified (Amatya et al., 2015; Chang et al., 2019; Ding et al., 2017; Pan et al., 2020; K. Yang et al., 2008). Therefore, we used this method to gap‐fill the missing data.…”

Section: Methodsmentioning

confidence: 99%

An Enhanced MOD16 Evapotranspiration Model for the Tibetan Plateau During the Unfrozen Season

Ling

Chen

et al. 2021

JGR Atmospheres

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Evapotranspiration (ET) is composed of soil evaporation (ETs), canopy transpiration (ETc), and canopy intercepted water evaporation (ETw), and it plays an indispensable role in the water and energy cycles of land surface processes. More accurate estimations of variations in ET are essential for natural hazard monitoring and water resource management. An improved algorithm for ETs with soil moisture and texture (SMT) and an optimized ETc based on the MOD16 model (MOD16‐STM) are proposed for the cold, arid, and semiarid regions of the Tibetan Plateau (TP). The nonlinear relationships between the soil surface resistance (rss) and soil surface hydration state in different soil textures were redefined by using five flux tower measurements over the TP. The value of the mean potential stomatal conductance per unit leaf area (CL) used for ETc calculation in grasslands was optimized at 0.0038 (m s−1). The MOD16‐STM was compared with the MOD16 and a soil water index‐based Priestley‐Taylor algorithm (SWI‐PT) at five independent sites. The results showed that the half‐hourly, daily, and monthly estimations from the MOD16‐STM were closer to observations than those from the other two models. The results indicated that the MOD16‐STM increased R2 by 0.2/0.05 and the index of agreement by 0.37/0.23 and deceased RMSE by 43.89/42.77 W m−2 and the absolute mean bias (|MB|) by 46.23/45.89 W m−2, when compared to the results of the MOD16 at daily/monthly scales. The results suggested that the MOD16‐STM will produce more accurate ET estimates over the flux sites and has great potential for ET estimation and land surface model improvement for the TP region.

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Section: Methodsmentioning

confidence: 99%

An Enhanced MOD16 Evapotranspiration Model for the Tibetan Plateau During the Unfrozen Season

Ling

Chen

et al. 2021

JGR Atmospheres

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“…The increasing trend in sensible heat flux during April and May can be attributed to increased net radiation flux under persistent irrigation land used for agriculture and urban areas. However, Amatya et al [56] indicated that the increase in wind speed and the ground-air temperature difference could increase sensible heat flux.…”

Section: Heat Fluxes Analysismentioning

confidence: 99%

Mapping and Assessment of Evapotranspiration over Different Land-Use/Land-Cover Types in Arid Ecosystem

Biro¹,

Zeineldin²,

Alghannam³

2022

Climate Change in Asia and Africa - Examining the Biophysical and Social Consequences, and Society's Responses

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Evapotranspiration (ET) is an essential process for defining the mass and energy relationship between soil, crop and atmosphere. This study was conducted in the Eastern Region of Saudi Arabia, to estimate the actual daily, monthly and annual evapotranspiration (ETa) for different land-use systems using Landsat-8 satellite data during the year 2017/2018. Initially, six land-use and land-cover (LULC) types were identified, namely: date palm, cropland, bare land, urban land, aquatic vegetation, and open water bodies. The Surface Energy Balance Algorithm for Land (SEBAL) supported by climate data was used to compute the ETa. The SEBAL model outputs were validated using the FAO Penman-Monteith (FAO P-M) method coupled with field observation. The results showed that the annual ETa values varied between 800 and 1400 mm.year−1 for date palm, 2000 mm.year−1 for open water and 800 mm.year−1 for croplands. The validation measure showed a significant agreement level between the SEBAL model and the FAO P-M method with RMSE of 0.84, 0.98 and 1.38 mm.day−1 for date palm, open water and cropland respectively. The study concludes that the ETa produced from the satellite data and the SEBAL model is useful for water resource management under arid ecosystem of the study area.

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“…The net radiation R n can be obtained through the surface radiation balance equation [57]: (15) where α is the land surface albedo (Equation (14)), σ is Stefan-Boltzmann constant (5.67 × 10 −8 W m −2 ·K −4 ). DSR and DLR are the incoming short and long wave radiation fluxes, respectively (W/m 2 ).…”

Section: The Performance Of the Improved Parameterization Scheme Maimmentioning

confidence: 99%

Estimating Surface Soil Heat Flux in Permafrost Regions Using Remote Sensing-Based Models on the Northern Qinghai-Tibetan Plateau under Clear-Sky Conditions

Cheng

Wang

et al. 2019

Remote Sensing

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The ground surface soil heat flux (G 0 ) quantifies the energy transfer between the atmosphere and the ground through the land surface. However; it is difficult to obtain the spatial distribution of G 0 in permafrost regions because of the limitation of in situ observation and complication of ground surface conditions. This study aims at developing an improved G 0 parameterization scheme applicable to permafrost regions of the Qinghai-Tibet Plateau under clear-sky conditions. We validated several existing remote sensing-based models to estimate G 0 by analyzing in situ measurement data. Based on the validation of previous models on G 0 ; we added the solar time angle to the G 0 parameterization scheme; which considered the phase difference problem.The maximum values of RMSE and MAE between "measured G 0 " and simulated G 0 using the improved parameterization scheme and in situ data were calculated to be 6.102 W/m 2 and 5.382 W/m 2 ; respectively. When the error of the remotely sensed land surface temperature is less than 1 K and the surface albedo measured is less than 0.02; the accuracy of estimates based on remote sensing data for G 0 will be less than 5%. MODIS data (surface reflectance; land surface temperature; and emissivity) were used to calculate G 0 in a 10 x 10 km region around Tanggula site; which is located in the continuous permafrost region with long-term records of meteorological and permafrost parameters. The results obtained by the improved scheme and MODIS data were consistent with the observation. This study enhances our understanding of the impacts of climate change on the ground thermal regime of permafrost and the land surface processes between atmosphere and ground surface in cold regions.

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Recent trends (2003–2013) of land surface heat fluxes on the southern side of the central Himalayas, Nepal

Cited by 12 publications

References 73 publications

An Enhanced MOD16 Evapotranspiration Model for the Tibetan Plateau During the Unfrozen Season

An Enhanced MOD16 Evapotranspiration Model for the Tibetan Plateau During the Unfrozen Season

Mapping and Assessment of Evapotranspiration over Different Land-Use/Land-Cover Types in Arid Ecosystem

Estimating Surface Soil Heat Flux in Permafrost Regions Using Remote Sensing-Based Models on the Northern Qinghai-Tibetan Plateau under Clear-Sky Conditions

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