scholarly journals Drought onset and propagation into soil moisture and grassland vegetation responses during the 2012–2019 major drought in Southern California

2021 ◽  
Vol 25 (6) ◽  
pp. 3713-3729
Author(s):  
Maria Magdalena Warter ◽  
Michael Bliss Singer ◽  
Mark O. Cuthbert ◽  
Dar Roberts ◽  
Kelly K. Caylor ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Sierra Nevada ◽  
Rainy Season ◽  
Southern California ◽  
Severe Drought ◽  
Climate Change Scenarios ◽  
Evaporative Demand ◽  
Coastal Site ◽  
Vegetation Responses

Abstract. Despite clear signals of regional impacts of the recent severe drought in California, e.g., within Californian Central Valley groundwater storage and Sierra Nevada forests, our understanding of how this drought affected soil moisture and vegetation responses in lowland grasslands is limited. In order to better understand the resulting vulnerability of these landscapes to fire and ecosystem degradation, we aimed to generalize drought-induced changes in subsurface soil moisture and to explore its effects within grassland ecosystems of Southern California. We used a high-resolution in situ dataset of climate and soil moisture from two grassland sites (coastal and inland), alongside greenness (Normalized Difference Vegetation Index) data from Landsat imagery, to explore drought dynamics in environments with similar precipitation but contrasting evaporative demand over the period 2008–2019. We show that negative impacts of prolonged precipitation deficits on vegetation at the coastal site were buffered by fog and moderate temperatures. During the drought, the Santa Barbara region experienced an early onset of the dry season in mid-March instead of April, resulting in premature senescence of grasses by mid-April. We developed a parsimonious soil moisture balance model that captures dynamic vegetation–evapotranspiration feedbacks and analyzed the links between climate, soil moisture, and vegetation greenness over several years of simulated drought conditions, exploring the impacts of plausible climate change scenarios that reflect changes to precipitation amounts, their seasonal distribution, and evaporative demand. The redistribution of precipitation over a shortened rainy season highlighted a strong coupling of evapotranspiration to incoming precipitation at the coastal site, while the lower water-holding capacity of soils at the inland site resulted in additional drainage occurring under this scenario. The loss of spring rains due to a shortening of the rainy season also revealed a greater impact on the inland site, suggesting less resilience to low moisture at a time when plant development is about to start. The results also suggest that the coastal site would suffer disproportionally from extended dry periods, effectively driving these areas into more extreme drought than previously seen. These sensitivities suggest potential future increases in the risk of wildfires under climate change, as well as increased grassland ecosystem vulnerability.

scholarly journals Onset and propagation of drought into soil moisture and vegetation responses during the 2012–2019 drought in Southern California

2020 ◽  
Author(s):  
Maria Magdalena Warter ◽  
Michael Bliss Singer ◽  
Mark O. Cuthbert ◽  
Dar Roberts ◽  
Kelly K. Caylor ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Sierra Nevada ◽  
Southern California ◽  
Dry Season ◽  
Balance Model ◽  
Severe Drought ◽  
Climate Change Scenarios ◽  
Evaporative Demand ◽  
Vegetation Responses

Abstract. Despite clear signals of regional impacts of the recent severe drought in California within Central Valley groundwater storage and Sierra Nevada forests, our understanding of how this drought affected soil moisture and vegetation responses in lowland grasslands is limited. In order to better understand the resulting vulnerability of these landscapes to fire and ecosystem degradation, we aimed to generalize drought-induced changes in subsurface soil moisture and to explore its effects within grassland ecosystems of Southern California. We used a decadal in situ dataset of high-resolution climate and soil moisture from two grassland sites (coastal and inland), alongside greenness (NDVI) data from Landsat to explore drought dynamics in environments with similar precipitation but contrasting evaporative demand. Analysis of data from 2008 to 2019 showed that the negative impacts of prolonged net precipitation (netP) deficits on vegetation at the inlands site were buffered by fog and moderate temperatures at the coastal site. During the drought, the region experienced an early onset of the dry season, resulting in premature senescence of grasses by mid-April. We developed a parsimonious soil moisture balance model that captures dynamic vegetation–evapotranspiration feedbacks using netP–NDVI relationships as a leading indicator. We then analyzed the links between climate, soil moisture, and vegetation greenness over decadal timescales, exploring the impacts of plausible climate change scenarios that reflect changes to precipitation amounts, their seasonal distribution, and evaporative demand. We found that all scenarios generate early, extreme soil moisture deficits during drought below a vegetation stress threshold, further intensifying early dry season onset and vegetation die-off. These changes suggest potential increases in the risk of wildfires in this and similar regions under climate change, as well as increased grassland ecosystem vulnerability.

Assess 21st century Flash Drought in the United States using high resolution regional climate models

2021 ◽  
Author(s):  
Brandi Gamelin ◽  
Jiali Wang ◽  
V. Rao Kotamarthi
Keyword(s):  
Climate Change ◽  
United States ◽  
Soil Moisture ◽  
Climate Models ◽  
Wrf Model ◽  
The United States ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Regional Variability ◽  
Groundwater Levels

<p>Flash droughts are the rapid intensification of drought conditions generally associated with increased temperatures and decreased precipitation on short time scales.  Consequently, flash droughts are responsible for reduced soil moisture which contributes to diminished agricultural yields and lower groundwater levels. Drought management, especially flash drought in the United States is vital to address the human and economic impact of crop loss, diminished water resources and increased wildfire risk. In previous research, climate change scenarios show increased growing season (i.e. frost-free days) and drying in soil moisture over most of the United States by 2100. Understanding projected flash drought is important to assess regional variability, frequency and intensity of flash droughts under future climate change scenarios. Data for this work was produced with the Weather Research and Forecasting (WRF) model. Initial and boundary conditions for the model were supplied by CCSM4, GFDL-ESM2G, and HadGEM2-ES and based on the 8.5 Representative Concentration Pathway (RCP8.5). The WRF model was downscaled to a 12 km spatial resolution for three climate time frames: 1995-2004 (Historical), 2045-2054 (Mid), and 2085-2094 (Late).  A key characteristic of flash drought is the rapid onset and intensification of dry conditions. For this, we identify onset with vapor pressure deficit during each time frame. Known flash drought cases during the Historical run are identified and compared to flash droughts in the Mid and Late 21<sup>st</sup> century.</p>

scholarly journals Hydrologic sensitivity of the Upper San Joaquin River Watershed in California to climate change scenarios

2012 ◽  
Vol 44 (4) ◽  
pp. 723-736 ◽  
Author(s):  
Zili He ◽  
Zhi Wang ◽  
C. John Suen ◽  
Xiaoyi Ma
Keyword(s):  
Climate Change ◽  
Sierra Nevada ◽  
Climate Change Scenarios ◽  
Intergovernmental Panel ◽  
Hydrological Simulation ◽  
River Watershed ◽  
System Sensitivity ◽  
Hspf Model ◽  
San Joaquin River ◽  
San Joaquin River Watershed

To examine the hydrological system sensitivity of the southern Sierra Nevada Mountains of California to climate change scenarios (CCS), five headwater basins in the snow-dominated Upper San Joaquin River Watershed (USJRW) were selected for hydrologic simulations using the Hydrological Simulation Program-Fortran (HSPF) model. A pre-specified set of CCS as projected by the Intergovernmental Panel on Climate Change (IPCC) were adopted as inputs for the hydrologic analysis. These scenarios include temperature increases between 1.5 and 4.5 °C and precipitation variation between 80 and 120% of the baseline conditions. The HSPF model was calibrated and validated with measured historical data. It was then used to simulate the hydrologic responses of the watershed to the projected CCS. Results indicate that the streamflow of USJRW is sensitive to the projected climate change. The total volume of annual streamflow would vary between −41 and +16% compared to the baseline years (1970–1990). Even if the precipitation remains unchanged, the total annual flow would still decrease by 8–23% due to temperature increases. A larger portion of the streamflow would occur earlier in the water year by 15–46 days due to the temperature increases, causing higher seasonal variability of streamflow.

scholarly journals Soil moisture regimes in Mexico in a global 1.5°C warming scenario

2019 ◽  
Vol 11 (4) ◽  
pp. 465-482 ◽  
Author(s):  
Jesus David Gomez Diaz ◽  
Alejandro I. Monterroso ◽  
Patricia Ruiz ◽  
Lizeth M. Lechuga ◽  
Ana Cecilia Conde Álvarez ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Regional Scale ◽  
Moisture Regime ◽  
Monthly Precipitation ◽  
Climate Change Scenarios ◽  
Content Type ◽  
Warming Scenario ◽  
Moisture Regimes ◽  
Gfdl Model

Purpose This study aims to present the climate change effect on soil moisture regimes in Mexico in a global 1.5°C warming scenario. Design/methodology/approach The soil moisture regimes were determined using the Newhall simulation model with the database of mean monthly precipitation and temperature at a scale of 1: 250,000 for the current scenario and with the climate change scenarios associated with a mean global temperature increase of 1.5°C, considering two Representative Concentration Pathways, 4.5 and 8.5 W/m2 and three general models of atmospheric circulation, namely, GFDL, HADGEM and MPI. The different vegetation types of the country were related to the soil moisture regimes for current conditions and for climate change. Findings According to the HADGEM and MPI models, almost the entire country is predicted to undergo a considerable increase in soil moisture deficit, and part of the areas of each moisture regime will shift to the next drier regime. The GFDL model also predicts this trend but at smaller proportions. Originality/value The changes in soil moisture at the regional scale that reveal the impacts of climate change and indicate where these changes will occur are important elements of the knowledge concerning the vulnerability of soils to climate change. New cartography is available in Mexico.

scholarly journals Severe Drought in Finland: Modeling Effects on Water Resources and Assessing Climate Change Impacts

2019 ◽  
Vol 11 (8) ◽  
pp. 2450 ◽  
Author(s):  
Noora Veijalainen ◽  
Lauri Ahopelto ◽  
Mika Marttunen ◽  
Jaakko Jääskeläinen ◽  
Ritva Britschgi ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Water Supply ◽  
Impact Analysis ◽  
Climate Change Impacts ◽  
Water Levels ◽  
Severe Drought ◽  
Climate Change Scenarios ◽  
Economic Sectors ◽  
The Impact

Severe droughts cause substantial damage to different socio-economic sectors, and even Finland, which has abundant water resources, is not immune to their impacts. To assess the implications of a severe drought in Finland, we carried out a national scale drought impact analysis. Firstly, we simulated water levels and discharges during the severe drought of 1939–1942 (the reference drought) in present-day Finland with a hydrological model. Secondly, we estimated how climate change would alter droughts. Thirdly, we assessed the impact of drought on key water use sectors, with a focus on hydropower and water supply. The results indicate that the long-lasting reference drought caused the discharges to decrease at most by 80% compared to the average annual minimum discharges. The water levels generally fell to the lowest levels in the largest lakes in Central and South-Eastern Finland. Climate change scenarios project on average a small decrease in the lowest water levels during droughts. Severe drought would have a significant impact on water-related sectors, reducing water supply and hydropower production. In this way drought is a risk multiplier for the water–energy–food security nexus. We suggest that the resilience to droughts could be improved with region-specific drought management plans and by including droughts in existing regional preparedness exercises.

scholarly journals Terrestrial ecosystems response to future changes in climate and atmospheric CO<sub>2</sub> concentration

2014 ◽  
Vol 11 (3) ◽  
pp. 3581-3614 ◽  
Author(s):  
V. K. Arora ◽  
G. J. Boer
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
High Latitude ◽  
Atmospheric Co2 ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Terrestrial Carbon ◽  
Simulated Precipitation ◽  
Atmospheric Carbon ◽  
Amazonian Region

Abstract. The response of the terrestrial carbon cycle to future changes in climate and atmospheric CO2 is assessed by analyzing simulations, for the 2006–2100 period, made with the second generation Canadian Earth system model (CanESM2) for the RCP 2.6, RCP 4.5 and RCP 8.5 climate change scenarios. Our interest is in the extent to which global terrestrial carbon pools and sinks, in particular those of the Amazonian region, are vulnerable to the adverse effects of climate change. CanESM2 results indicate that land remains an overall sink of atmospheric carbon for the 2006–2100 period. The net carbon uptake by land in response to changes in climate and atmospheric CO2 is close to 20, 80 and 140 Pg C for the RCP 2.6, 4.5 and 8.5 scenarios, respectively. The latitudinal structure of future atmosphere–land CO2 flux remains similar to that observed for the historical period with northern mid- to high-latitude regions gaining carbon from the atmosphere while the tropics remain either carbon neutral or a modest source of atmospheric carbon depending on scenario. These changes occur in conjunction with simulated precipitation and soil moisture increases over northern mid- and high-latitude land regions and precipitation and soil moisture decreases over the South American continent in all scenarios. Compared to other regions of the globe, which are either carbon sinks or near neutral, the Amazonian region is simulated to be a net source of carbon during the 21st century. Moreover, and unexpectedly, the rate of carbon loss to the atmosphere from the Amazonian region is largely independent of the differences between the three scenarios considered.

scholarly journals Projeções Climáticas das Alterações da Quantidade de Água no Solo Disponível para o Cultivo de Soja (Climate Projections of Quality Changes in Water Available on the Ground for Cultivation of Soybeans)

2012 ◽  
Vol 5 (4) ◽  
pp. 807
Author(s):  
Luciana Da Silva Mieres ◽  
Claudinéia Brazil Saldanha ◽  
Arthur Da Fontoura Tschiedel ◽  
Rogério De Lima Saldanha ◽  
Maria Angélica Gonçalves Cardoso
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Agricultural Productivity ◽  
Rio Grande ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Quality Changes ◽  
Rio Grande Do Sul ◽  
International Panel ◽  
Impacts Of Climate Change

As alterações climáticas estão associadas a graves impactos na agricultura uma vez que o crescimento e o desenvolvimento das culturas dependem diretamente do clima e das interações solo-atmosfera. A umidade do solo é uma informação fundamental no planejamento agrícola, subsidiando a definição das datas de plantio, necessidades de irrigação e produtividades agrícolas. O presente estudo objetivou avaliar os impactos das mudanças climáticas na umidade do solo para uma região de cultura de soja do estado do Rio Grande do Sul através dos cenários estabelecidos pelo IPCC (International Panel on Climate Change). Os resultados indicaram uma tendência ao aumento da precipitação, favorecendo o aumento da taxa de umidade do solo na região do médio alto Uruguai. Em síntese, o fator de umidade do solo apresentou condições favoráveis ao desenvolvimento vegetal e pelos resultados apresentados, verifica-se que o modelo de previsão de umidade do solo, analisado em conjunto com os cenários do IPCC, são importantes ferramentas para os estudos dos impactos das mudanças climáticas na produtividade agrícola. Palavras chaves: mudanças climáticas, soja, umidade do solo.   Climate Projections of Quality Changes in Water Available on the Ground for Cultivation of Soybeans   ABSTRACT Climate change is associated with serious impacts on agriculture since the crop growth and development depend directly on the climate and soil-atmosphere interactions. Soil moisture is fundamental information in agricultural planning, helping to define the dates of planting, irrigation needs, and agricultural productivity. In this study was evaluated the impacts of climate change in moisture soil to a region of the soybean crop in the state of Rio Grande do Sul using the IPCC (International Panel on Climate Change) scenarios set. The results indicated a tendency to increased rainfall, favoring an increase in the rate of soil moisture in the region of the middle upper Uruguay. The factor of soil moisture showed favorable conditions for plant development and the results presented showed that prediction model of soil moisture analyzed in conjunction with the IPCC scenarios are important tools for studies of the impacts of climate change on agricultural productivity. Keywords: Climate change, soybean, soil moisture.

scholarly journals Soil methane oxidation in both dry and wet temperate eucalypt forests shows a near-identical relationship with soil air-filled porosity

2017 ◽  
Vol 14 (2) ◽  
pp. 467-479 ◽  
Author(s):  
Benedikt J. Fest ◽  
Nina Hinko-Najera ◽  
Tim Wardlaw ◽  
David W. T. Griffith ◽  
Stephen J. Livesley ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Climate Change Scenarios ◽  
Soil Air ◽  
Eucalypt Forest ◽  
Soil Atmosphere ◽  
Forest Sites ◽  
Ch4 Uptake ◽  
Eucalypt Forests ◽  
The Impact

Abstract. Well-drained, aerated soils are important sinks for atmospheric methane (CH4) via the process of CH4 oxidation by methane-oxidising bacteria (MOB). This terrestrial CH4 sink may contribute towards climate change mitigation, but the impact of changing soil moisture and temperature regimes on CH4 uptake is not well understood in all ecosystems. Soils in temperate forest ecosystems are the greatest terrestrial CH4 sink globally. Under predicted climate change scenarios, temperate eucalypt forests in south-eastern Australia are predicted to experience rapid and extreme changes in rainfall patterns, temperatures and wild fires. To investigate the influence of environmental drivers on seasonal and inter-annual variation of soil–atmosphere CH4 exchange, we measured soil–atmosphere CH4 exchange at high-temporal resolution (<  2 h) in a dry temperate eucalypt forest in Victoria (Wombat State Forest, precipitation 870 mm yr−1) and in a wet temperature eucalypt forest in Tasmania (Warra Long-Term Ecological Research site, 1700 mm yr−1). Both forest soil systems were continuous CH4 sinks of −1.79 kg CH4 ha−1 yr−1 in Victoria and −3.83 kg CH4 ha−1 yr−1 in Tasmania. Soil CH4 uptake showed substantial temporal variation and was strongly controlled by soil moisture at both forest sites. Soil CH4 uptake increased when soil moisture decreased and this relationship explained up to 90 % of the temporal variability. Furthermore, the relationship between soil moisture and soil CH4 flux was near-identical at both forest sites when soil moisture was expressed as soil air-filled porosity (AFP). Soil temperature only had a minor influence on soil CH4 uptake. Soil nitrogen concentrations were generally low and fluctuations in nitrogen availability did not influence soil CH4 uptake at either forest site. Our data suggest that soil MOB activity in the two forests was similar and that differences in soil CH4 exchange between the two forests were related to differences in soil moisture and thereby soil gas diffusivity. The differences between forest sites and the variation in soil CH4 exchange over time could be explained by soil AFP as an indicator of soil moisture status.

scholarly journals Terrestrial ecosystems response to future changes in climate and atmospheric CO<sub>2</sub> concentration

2014 ◽  
Vol 11 (15) ◽  
pp. 4157-4171 ◽  
Author(s):  
V. K. Arora ◽  
G. J. Boer
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
High Latitude ◽  
Atmospheric Co2 ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Terrestrial Carbon ◽  
Simulated Precipitation ◽  
Atmospheric Carbon ◽  
Amazonian Region

Abstract. The response of the terrestrial carbon cycle to future changes in climate and atmospheric CO2 is assessed by analysing simulation results for the 2006–2100 period made with the second generation Canadian Earth system model (CanESM2) for the RCP 2.6, RCP 4.5 and RCP 8.5 climate change scenarios. Our interest is in the extent to which global terrestrial carbon pools and sinks, in particular those of the Amazonian region, are vulnerable to the adverse effects of climate change. CanESM2 results indicate that land remains an overall sink of atmospheric carbon for the 2006–2100 period. The net carbon uptake by land in response to changes in climate and atmospheric CO2 is close to 20, 80 and 140 Pg C for the RCP 2.6, 4.5 and 8.5 scenarios, respectively. The latitudinal structure of future atmosphere–land CO2 flux remains similar to that observed for the historical period with northern mid- to high-latitude regions gaining carbon from the atmosphere while the tropics remain either carbon neutral or a modest source of atmospheric carbon depending on scenario. These changes occur in conjunction with simulated precipitation and soil moisture increases over northern mid- and high-latitude land regions and precipitation and soil moisture decreases over the South American continent in all scenarios. Compared to other regions of the globe, which are either carbon sinks or near neutral, the Amazonian region is simulated to be a net source of carbon during the 21st century. Moreover, and unexpectedly, the rate of carbon loss to the atmosphere from the Amazonian region is largely independent of the differences between the three scenarios considered.

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