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.

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 Investigating the Spatio-Temporal Variation of Soil Moisture and Agricultural Drought towards Supporting Water Resources Management in the Red River Basin of Vietnam

2021 ◽  
Vol 13 (9) ◽  
pp. 4926
Author(s):  
Nguyen Duc Luong ◽  
Nguyen Hoang Hiep ◽  
Thi Hieu Bui
Keyword(s):  
Soil Moisture ◽  
River Basin ◽  
Temporal Dynamics ◽  
Regional Scale ◽  
Dry Season ◽  
Red River ◽  
Agricultural Drought ◽  
Severe Drought ◽  
Red River Basin ◽  
Spatio Temporal

The increasing serious droughts recently might have significant impacts on socioeconomic development in the Red River basin (RRB). This study applied the variable infiltration capacity (VIC) model to investigate spatio-temporal dynamics of soil moisture in the northeast, northwest, and Red River Delta (RRD) regions of the RRB part belongs to territory of Vietnam. The soil moisture dataset simulated for 10 years (2005–2014) was utilized to establish the soil moisture anomaly percentage index (SMAPI) for assessing intensity of agricultural drought. Soil moisture appeared to co-vary with precipitation, air temperature, evapotranspiration, and various features of land cover, topography, and soil type in three regions of the RRB. SMAPI analysis revealed that more areas in the northeast experienced severe droughts compared to those in other regions, especially in the dry season and transitional months. Meanwhile, the northwest mainly suffered from mild drought and a slightly wet condition during the dry season. Different from that, the RRD mainly had moderately to very wet conditions throughout the year. The areas of both agricultural and forested lands associated with severe drought in the dry season were larger than those in the wet season. Generally, VIC-based soil moisture approach offered a feasible solution for improving soil moisture and agricultural drought monitoring capabilities at the regional scale.

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.

Assessing the options for the operational mapping of the soil moisture content in the European Alps

2021 ◽  
Author(s):  
Felix Greifeneder ◽  
Klaus Haslinger ◽  
Georg Seyerl ◽  
Claudia Notarnicola ◽  
Massimiliano Zappa ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Temporal Dynamics ◽  
Hydrological Cycle ◽  
Balance Model ◽  
High Mountain ◽  
European Alps ◽  
Entire Area ◽  
Advantages And Disadvantages ◽  
Hourly Data

<p>Soil Moisture (SM) is one of the key observable variables of the hydrological cycle and therefore of high importance for many disciplines, from meteorology to agriculture. This contribution presents a comparison of different products for the mapping of SM. The aim was to identify the best available solution for the operational monitoring of SM as a drought indicator for the entire area of the European Alps, to be applied in the context of the Interreg Alpine Space project, the Alpine Drought Observatory.</p><p>The following datasets were considered: Soil Water Index (SWI) of the Copernicus Global Land Service [1]; ERA5 [2]; ERA5-Land [3]; UERRA MESCAN-SURFEX land-surface component [4]. All four datasets offer a different set of advantages and disadvantages related to their spatial resolution, update frequency and latency. As a reference, modelled SM time-series for 307 catchments in Switzerland were used [5]. Switzerland is well suited as a test case for the Alps, due to its different landscapes, from lowlands to high mountain.</p><p>The intercomparison was based on a correlation analysis of daily absolute SM values and the daily anomalies. Furthermore, the probability to detect certain events, such as persistent dry conditions, was evaluated for each of the SM datasets. First results showed that the temporal dynamics (both in terms of absolute values as well as anomalies) of the re-analysis datasets show a high correlation to the reference. A clear gradient, from the lowlands in the north to the high mountains in the south, with decreasing correlation is evident. The SWI data showed weak correlations to the temporal dynamics of the reference in general. Especially, during spring and the first part of the summer SM is significantly underestimated. This might be related to the influence of snowmelt, which is not taken into account in the two-layer water balance model used to model SM for deeper soil layers. Low coverage in the high mountain areas hampered a thorough comparison with the reference in these areas.</p><p>The results presented here are the foundation for selecting a suitable source for the operational mapping of SM for the Alpine Drought Observatory. The next steps will be to test the potential of MESCAN-SURFEX and ERA5-Land for the downscaling of ERA5 to take advantage of the low latency of ERA5 and the improved spatial detail of the other two datasets.  </p><p>Literature:</p><p>[1]  B. Bauer-marschallinger et al., “Sentinel-1 : Harnessing Assets and Overcoming Obstacles,” IEEE Trans. Geosci. Remote Sens., vol. 57, no. 1, pp. 520–539, 2019, doi: 10.1109/TGRS.2018.2858004.</p><p>[2]  H. Hersbach et al., “ERA5 hourly data on single levels from 1979 to present.” Copernicus Climate Change Service (C3S) Climate Data Store (CDS), 2018.</p><p>[3]  Copernicus Climate Change Service, “ERA5-Land hourly data from 2001 to present.” ECMWF, 2019, doi: 10.24381/CDS.E2161BAC.</p><p>[4]  E. Bazile, et al., “MESCAN-SURFEX Surface Analysis. Deliverable D2.8 of the UERRA Project,” 2017. Accessed: Jan. 11, 2020. [Online]. Available: http://www.uerra.eu/publications/deliverable-reports.html.</p><p>[5]  Brunner, et al.: Extremeness of recent drought events in    Switzerland: dependence on variable and return period choice, Nat. Hazards Earth Syst. Sci., 19, 2311–2323, https://doi.org/10.5194/nhess-19-2311-2019, 2019.</p>

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.

The Effect of Climate Change on River Flow and Snow Cover in the NOPEX Area Simulated by a Simple Water Balance Model

1997 ◽  
Vol 28 (4-5) ◽  
pp. 273-282 ◽  
Author(s):  
C-Y Xu ◽  
Sven Halldin
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Snow Cover ◽  
Annual Runoff ◽  
Snow Accumulation ◽  
Water Balance Model ◽  
Annual Precipitation ◽  
Balance Model ◽  
Climate Change Scenarios ◽  
Average Annual Runoff

Within the next few decades, changes in global temperature and precipitation patterns may appear, especially at high latitudes. A simple monthly water-balance model of the NOPEX basins was developed and used for the purposes of investigating the effects on water availability of changes in climate. Eleven case study catchments were used together with a number of climate change scenarios. The effects of climate change on average annual runoff depended on the ratio of average annual runoff to average annual precipitation, with the greatest sensitivity in the catchments with lowest runoff coefficients. A 20% increase in annual precipitation resulted in an increase in annual runoff ranging from 31% to 51%. The greatest changes in monthly runoff were in winter (from December to March) whereas the smallest changes were found in summer. The time of the highest spring flow changed from April to March. An increase in temperature by 4°C greatly shortened the time of snow cover and the snow accumulation period. The maximum amount of snow during these short winters diminished by 50% for the NOPEX area even with an assumed increase of total precipitation by 20%.

Modelling the impacts of climate change and land-use change on the hydrology of Vietnam’s river basins

2020 ◽  
Author(s):  
Francesca Moschini ◽  
Iacopo Federico Ferrario ◽  
Barbara Hofmann
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Land Use Planning ◽  
Weighted Average ◽  
Surface Fluxes ◽  
Base Flow ◽  
Balance Model ◽  
Climate Change Scenarios ◽  
Hydrological Fluxes

<p>Quantifying how land-use change affects hydrological components is a challenge in hydrological science. It is not yet clear how changes in land use relate to runoff extremes and why some catchments are more sensitive to land-use change than others. Identifying which areas are hydrologically more sensitive to land-use change can lead to better land-use planning, reduction of the impacts of extreme rainfall events and extended dry periods. In this study we aim to quantify how land-use change and climate change are affecting the hydrological response of  Vietnam’s basins. Over the past decades the country’s land use has shifted from forest to agriculture, with very high production of rice, coffee, tea, pepper and sugar cane.</p><p>We combine the historical, the Intergovernmental Panel on Climate Change’s (IPCC) Representative Concentration Pathway (RCP) RCP4.5 and RCP8.5 climate change scenarios developed for Vietnam, with two different land cover maps (from the years 1992 and 2017). The combined and separate effect of land use and climate change are assessed and the most sensitive to change areas are identified. The Variable infiltration Capacity (VIC) surface water and energy balance model applied here is a grid-based model that calculates evapotranspiration, runoff, base flow, soil moisture and other hydrological fluxes. Surface heterogeneity within VIC is represented by a tiled approach, whereby the surface of each grid-box comprises fractions of the different surface types. For each surface type of the grid-box, the energy and water balances are solved, and a weighted average is calculated from the individual surface fluxes for each grid-box. Hydrological fluxes were compared for each grid cell and basin to analyse the degree of difference between the scenarios.</p><p>Significant changes in future hydrologic fluxes arise under both climate change scenarios pointing towards a severe increase in hydrological extremes. The changes in all the examined hydrological components are greater in the combined land-use and climate change experiments.</p>

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