Calculating Thornthwaite and Mather's actual evapotranspiration using an approximating function

1984 ◽  
Vol 14 (3) ◽  
pp. 466-467 ◽  
Author(s):  
J. Pastor ◽  
W. M. Post
Keyword(s):  
Soil Water ◽  
Exponential Function ◽  
Water Loss ◽  
Water Storage ◽  
Field Capacity ◽  
Actual Evapotranspiration ◽  
Soil Water Storage ◽  
Negative Exponential Function ◽  
Negative Exponential

A simple negative exponential function is presented which relates soil water storage to a maximum storage value (field capacity) and accumulated potential water loss. This formula summarizes 10 tables from Thornthwaite and Mather (Publications in Climatology, 10: 183–311, 1957) needed to calculate actual evapotranspiration (AET). Comparisons are presented for values predicted by this formula and Thornthwaite and Mather's tabulated values.

A decreasing trend in global soil water storage from 1981 to 2017

2021 ◽  
Author(s):  
XinRui Luo ◽  
Shaoda Li ◽  
Wunian Yang ◽  
Liang Liu ◽  
Xiaolu Tang
Keyword(s):  
Soil Water ◽  
Water Loss ◽  
Root Zone ◽  
Carbon Sink ◽  
Temporal Trends ◽  
Water Storage ◽  
Terrestrial Ecosystems ◽  
Environmental Drivers ◽  
Soil Water Storage ◽  
Soil Drought

<p>Soil water storage serves as a vital resource of the terrestrial ecosystems, and it can significantly influence water cycle and carbon cycling with the frequent occurrence of soil drought induced by land-atmosphere feedbacks. However, there are high variations and uncertainties of root zone soil water storage. This study applied comparison map profile (CMP), Mann-Kendall test, Theil-Sen estimate and partial correlation analysis to (1) estimate the global root zone (0~1 m) soil water storage, (2) and investigate the spatial and temporal patterns from 1981 to 2017 at the global scale, (3) and their relationships with environmental drivers (precipitation, temperature, potential evaportranspiration) using three soil moisture (SM) products – ERA-5, GLDAS and MERRA-2. Globally, the average annual soil water storage from 1981 to 2017 varied significantly, ranging from 138.3 (100 Pg a<sup>-1</sup>, 1 Pg = 10<sup>15</sup> g) in GLDAS to 342.6 (100 Pg a<sup>-1</sup>) in ERA-5. Soil water storage of the three SM products consistently showed a decreasing trend. However, the temporal trend of soil water storage among different climate zones was different, showing a decreasing trend in tropical, temperate and cold zones, but an increasing trend in polar regions. On the other hand, temporal trends in arid regions differed from ERA-5, GLDAS and MERRA-2. Spatially, the SM products differed greatly, particularly for boreal areas with D value higher for 2500 Mg ha<sup>-1</sup> a<sup>-1</sup> and CC value lower for -0.2 between GLDAS and MERRA-2. Over 1981 to 2017, water storage of more than 50% of the global land area suffered from a decreasing trend, especially in Africa and Northeastern of China. Precipitation was the main dominated driver for variation of soil water storage, and distribution varied in different SM products. In conclusion, a global decreasing trend in soil water storage indicate a water loss from soils, and how the water loss affecting carbon sink in terrestrial ecosystems under ongoing climate change needs further investigation.</p>

scholarly journals The Evaluation of Soil Water Storage in A Small Catchment in 2009 And 2010

2014 ◽  
Vol 17 (1) ◽  
pp. 1-4
Author(s):  
Ľuboš Jurík ◽  
Tatiana Kaletová
Keyword(s):  
Soil Water ◽  
Soil Profile ◽  
Water Storage ◽  
Vertical Direction ◽  
Field Capacity ◽  
Mean Value ◽  
Soil Water Storage ◽  
Volumetric Soil Water Content ◽  
Small Catchment ◽  
High Precipitation Events

Abstract The soil water storage in a soil profile was calculated from the measured values of volumetric soil water content by the Profile Probe PR2/6 (Delta-T Device Ltd.) in the Bocegaj catchment in the depth up to 1m. The monitored season in the year 2009 followed after a dry season, and in the year 2010, rainfalls were above the average values. The soil water storage was higher than the mean value of field capacity during the season with high precipitation events. With a decreased amount of rainfalls, rising air temperature and crops growing, the soil water storage was in recession. In the vertical direction, the volumetric soil moisture as well as soil water storage in every soil profile have their characteristic progresses.

scholarly journals Field Assessment of Soil Water Storage and Actual Evapotranspiration of Rainfed Maize (<i>Zea mays</i> L.) Genotypes in a Coastal Savannah Environment

2012 ◽  
Vol 02 (03) ◽  
pp. 213-222 ◽  
Author(s):  
Justice Okona Frimpong ◽  
Marcus Quaynor Addy ◽  
Emmanuel Ofori Ayeh ◽  
Harry Mensah Amoatey ◽  
Jacob Teye Kutufam ◽  
...  
Keyword(s):  
Zea Mays ◽  
Soil Water ◽  
Water Storage ◽  
Actual Evapotranspiration ◽  
Soil Water Storage ◽  
Field Assessment

scholarly journals Soil-water dynamics and unsaturated storage during snowmelt following wildfire

2012 ◽  
Vol 9 (1) ◽  
pp. 441-483
Author(s):  
B. A. Ebel ◽  
E. S. Hinckley ◽  
D. A. Martin
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Storage ◽  
Field Capacity ◽  
Water Dynamics ◽  
Soil Water Storage ◽  
Soil Water Dynamics ◽  
Near Surface ◽  
Snowmelt Period

Abstract. Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on snowmelt and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the snowmelt period by strong aspect controls on snowmelt and soil thawing. Here we present data and analysis from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ~1–2 °C warmer on average than north-facing burned soils and ~1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the snowmelt period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during snowmelt, soil-water storage at the end of the snowmelt period reached the value at field capacity for each plot, suggesting that post-snowmelt unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that snowmelt-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas.

scholarly journals Water storage change estimation from in situ shrinkage measurements of clay soils

2013 ◽  
Vol 17 (5) ◽  
pp. 1933-1949 ◽  
Author(s):  
B. te Brake ◽  
M. J. van der Ploeg ◽  
G. H. de Rooij
Keyword(s):  
Soil Water ◽  
Volume Change ◽  
Water Loss ◽  
Water Storage ◽  
Bulk Soil ◽  
Soil Water Storage ◽  
Dry Period ◽  
Soil Layers ◽  
Storage Change

Abstract. The objective of this study is to assess the applicability of clay soil elevation change measurements to estimate soil water storage changes, using a simplified approach. We measured moisture contents in aggregates by EC-5 sensors, and in multiple aggregate and inter-aggregate spaces (bulk soil) by CS616 sensors. In a long dry period, the assumption of constant isotropic shrinkage proved invalid and a soil moisture dependant geometry factor was applied. The relative overestimation made by assuming constant isotropic shrinkage in the linear (basic) shrinkage phase was 26.4% (17.5 mm) for the actively shrinking layer between 0 and 60 cm. Aggregate-scale water storage and volume change revealed a linear relation for layers ≥ 30 cm depth. The range of basic shrinkage in the bulk soil was limited by delayed drying of deep soil layers, and maximum water loss in the structural shrinkage phase was 40% of total water loss in the 0–60 cm layer, and over 60% in deeper layers. In the dry period, fitted slopes of the ΔV–ΔW relationship ranged from 0.41 to 0.56 (EC-5) and 0.42 to 0.55 (CS616). Under a dynamic drying and wetting regime, slopes ranged from 0.21 to 0.38 (EC-5) and 0.22 to 0.36 (CS616). Alternating shrinkage and incomplete swelling resulted in limited volume change relative to water storage change. The slope of the ΔV–ΔW relationship depended on the drying regime, measurement scale and combined effect of different soil layers. Therefore, solely relying on surface level elevation changes to infer soil water storage changes will lead to large underestimations. Recent and future developments might provide a basis for application of shrinkage relations to field situations, but in situ observations will be required to do so.

scholarly journals Ubiquitous Fractal Scaling and Filtering Behavior of Hydrologic Fluxes and Storages from A Mountain Headwater Catchment

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 613
Author(s):  
Ravindra Dwivedi ◽  
John F. Knowles ◽  
Christopher Eastoe ◽  
Rebecca Minor ◽  
Nathan Abramson ◽  
...  
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Storage ◽  
Actual Evapotranspiration ◽  
Soil Water Storage ◽  
Water Balance Components ◽  
Fractal Scaling ◽  
Wetting Properties ◽  
Soil Wetting

We used the weighted wavelet method to perform spectral analysis of observed long-term precipitation, streamflow, actual evapotranspiration, and soil water storage at a sub-humid mountain catchment near Tucson, Arizona, USA. Fractal scaling in precipitation and the daily change in soil water storage occurred up to a period of 14 days and corresponded to the typical duration of relatively wet and dry intervals. In contrast, fractal scaling could be observed up to a period of 0.5 years in streamflow and actual evapotranspiration. By considering long-term observations of hydrologic fluxes and storages, we show that, in contrast to previous findings, the phase relationships between water balance components changed with component period and were not perfectly in or out of phase at all periods. Self-averaging behavior was apparent, but the temporal scales over which this behavior was applicable differed among the various water balance components. Conservative tracer analysis showed that this catchment acted as a fractal filter by transforming white noise in the precipitation input signal to a 1/f flicker in the streamflow output signal by means of both spatial and temporal subsurface advection and dispersion processes and soil wetting properties. This study provides an improved understanding of hydrological filtering behavior in mountain critical zones that are critical sources of water and ecosystem services throughout the world.

scholarly journals Soil-water dynamics and unsaturated storage during snowmelt following wildfire

2012 ◽  
Vol 16 (5) ◽  
pp. 1401-1417 ◽  
Author(s):  
B. A. Ebel ◽  
E. S. Hinckley ◽  
D. A. Martin
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Storage ◽  
Field Capacity ◽  
Water Dynamics ◽  
Soil Water Storage ◽  
Soil Water Dynamics ◽  
Near Surface ◽  
Snowmelt Period

Abstract. Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on snowmelt and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the snowmelt period by strong aspect controls on snowmelt and soil thawing. Here we present data from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ∼1–2 °C warmer on average than north-facing burned soils and ∼1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the snowmelt period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during snowmelt, soil-water storage at the end of the snowmelt period reached the value at field capacity for each plot, suggesting that post-snowmelt unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that the amount of snowmelt-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas.

scholarly journals Regression Models for Soil Water Storage Estimation Using the ESA CCI Satellite Soil Moisture Product: A Case Study in Northeast Portugal

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Tomás de Figueiredo ◽  
Ana Caroline Royer ◽  
Felícia Fonseca ◽  
Fabiana Costa de Araújo Schütz ◽  
Zulimar Hernández
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Regression Models ◽  
Meteorological Data ◽  
Water Storage ◽  
Model Performance ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
The Relationship

The European Space Agency Climate Change Initiative Soil Moisture (ESA CCI SM) product provides soil moisture estimates from radar satellite data with a daily temporal resolution. Despite validation exercises with ground data that have been performed since the product’s launch, SM has not yet been consistently related to soil water storage, which is a key step for its application for prediction purposes. This study aimed to analyse the relationship between soil water storage (S), which was obtained from soil water balance computations with ground meteorological data, and soil moisture, which was obtained from radar data, as affected by soil water storage capacity (Smax). As a case study, a 14-year monthly series of soil water storage, produced via soil water balance computations using ground meteorological data from northeast Portugal and Smax from 25 mm to 150 mm, were matched with the corresponding monthly averaged SM product. Linear (I) and logistic (II) regression models relating S with SM were compared. Model performance (r2 in the 0.8–0.9 range) varied non-monotonically with Smax, with it being the highest at an Smax of 50 mm. The logistic model (II) performed better than the linear model (I) in the lower range of Smax. Improvements in model performance obtained with segregation of the data series in two subsets, representing soil water recharge and depletion phases throughout the year, outlined the hysteresis in the relationship between S and SM.

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