Evapotranspiration Across the Rain-Snow Transition in a Semi-Arid Watershed

Mapping Intimacies ◽

10.22541/au.163725310.02361744/v1 ◽

2021 ◽

Author(s):

Maggi Kraft ◽

James McNamara

Keyword(s):

Soil Water ◽

Water Availability ◽

Snow Depth ◽

Energy Demand ◽

Environmental Parameters ◽

Growing Season ◽

Summer Season ◽

Season Length ◽

Spring Precipitation ◽

Growing Season Length

The snowpack regime influences the timing of soil water available for transpiration and synchrony with the evapotranspiration (ET) energy demand (air temperature, VPD, and shortwave radiation). Variability of snowmelt timing, soil water availability, and the energy demand results in heterogeneous ET rates throughout a watershed. In this study, we assess how ET and growing season length vary across five sites on an elevational gradient in the Dry Creek Watershed, ID, USA. We compared trends of daily and annual ET between 2012 and 2017 to environmental parameters of soil moisture, air temperature, vapor pressure deficit, snow cover, and precipitation and evaluate how ET varies between sites and what influences annual ET at each site. We observed three trends in ET across the watershed. The first trend is at the low elevation site where the snow cover is not continuous throughout the winter and rain is the dominant precipitation form. The first day of the growing season and ET occurs early in the season when the energy demand is low and soil water is available. Annual ET at the low elevation site is a balance between spring precipitation providing soil water into the summer season and limiting the ET energy demand. The second trend occurs at the middle elevation site located in the rain-snow transition. At this site, ET increases with snow depth and spring precipitation extending the soil water availability into the summer season. At the higher elevation sites, ET is aligned with the energy demand and limited by growing season length. At the high elevation sites, decreasing snow depth and spring precipitation and increasing spring air temperatures result in greater annual ET rates. The observations from this study highlight the influence of environmental parameters and the potential sensitivity of ET to climate change.

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El clima durante el Plioceno en la región de Santa María Amajac, Hidalgo, México

Botanical Sciences ◽

10.17129/botsci.1664 ◽

2017 ◽

pp. 71

Author(s):

Felisa J Aguilar ◽

Ma. Patricia Velasco-de León

Keyword(s):

Environmental Parameters ◽

Growing Season ◽

Specific Humidity ◽

Mean Annual Precipitation ◽

Mean Annual Temperature ◽

Season Length ◽

Leaf Analysis ◽

Growing Season Length ◽

Mean Temperature ◽

Santa Maria

The climate in which the Pliocene plant community of Santa María Amajac, Hidalgo, developed, was inferred using Climate Leaf Analysis Multivariate Program (CLAMP), which correlates leaf morphology with climate. The environmental parameters calculated were: mean annual temperature: 16.7 1.2C; warmest month mean temperature: 26.4 1.6C; coldest month mean temperature: 7C; growing season length: 9.2 months; mean growing season precipitation: 72 mm; three wettest months: 280 mm; three driest months: 62 mm: mean annual precipitation: 650 120 mm; relative humidity: 58%; specific humidity: 7.8 g/kg, and enthalpy: 309.5. These values suggest that the climate was a subhumid, temperate one, Ca(w)(w0)(e’).

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Characterizing Growing Season Length of Subtropical Coniferous Forests with a Phenological Model

Forests ◽

10.3390/f12010095 ◽

2021 ◽

Vol 12 (1) ◽

pp. 95

Author(s):

Yuan Gong ◽

Christina L. Staudhammer ◽

Susanne Wiesner ◽

Gregory Starr ◽

Yinlong Zhang

Keyword(s):

Climate Change ◽

Soil Water ◽

Prescribed Fire ◽

Water Availability ◽

Longleaf Pine ◽

Growing Season ◽

Soil Water Availability ◽

Future Climate Change ◽

Short Term ◽

Phenological Model

Understanding plant phenological change is of great concern in the context of global climate change. Phenological models can aid in understanding and predicting growing season changes and can be parameterized with gross primary production (GPP) estimated using the eddy covariance (EC) technique. This study used nine years of EC-derived GPP data from three mature subtropical longleaf pine forests in the southeastern United States with differing soil water holding capacity in combination with site-specific micrometeorological data to parameterize a photosynthesis-based phenological model. We evaluated how weather conditions and prescribed fire led to variation in the ecosystem phenological processes. The results suggest that soil water availability had an effect on phenology, and greater soil water availability was associated with a longer growing season (LOS). We also observed that prescribed fire, a common forest management activity in the region, had a limited impact on phenological processes. Dormant season fire had no significant effect on phenological processes by site, but we observed differences in the start of the growing season (SOS) between fire and non-fire years. Fire delayed SOS by 10 d ± 5 d (SE), and this effect was greater with higher soil water availability, extending SOS by 18 d on average. Fire was also associated with increased sensitivity of spring phenology to radiation and air temperature. We found that interannual climate change and periodic weather anomalies (flood, short-term drought, and long-term drought), controlled annual ecosystem phenological processes more than prescribed fire. When water availability increased following short-term summer drought, the growing season was extended. With future climate change, subtropical areas of the Southeastern US are expected to experience more frequent short-term droughts, which could shorten the region’s growing season and lead to a reduction in the longleaf pine ecosystem’s carbon sequestration capacity.

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Growing‐season length and soil microbes influence the performance of a generalist bunchgrass beyond its current range

Ecology ◽

10.1002/ecy.3095 ◽

2020 ◽

Vol 101 (9) ◽

Author(s):

Clifton P. Bueno de Mesquita ◽

Samuel A. Sartwell ◽

Steven K. Schmidt ◽

Katharine N. Suding

Keyword(s):

Soil Microbes ◽

Growing Season ◽

Season Length ◽

Current Range ◽

Growing Season Length

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Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

International Agrophysics ◽

10.1515/intag-2015-0026 ◽

2015 ◽

Vol 29 (2) ◽

pp. 129-135 ◽

Cited By ~ 3

Author(s):

Alina Danielewska ◽

Marek Urbaniak ◽

Janusz Olejnik

Keyword(s):

Air Temperature ◽

Measurement Data ◽

Growing Season ◽

Pine Forest ◽

Pine Forests ◽

Net Ecosystem Productivity ◽

Ecosystem Productivity ◽

Season Length ◽

Important Species ◽

Growing Season Length

Abstract The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

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