scholarly journals A Note on Soil Moisture Memory and Interactions with Surface Climate for Different Vegetation Types in the La Plata Basin

2015 ◽  
Vol 16 (2) ◽  
pp. 716-729 ◽  
Author(s):  
Anna A. Sörensson ◽  
Ernesto Hugo Berbery
Keyword(s):  
Soil Moisture ◽  
Surface Temperature ◽  
Statistical Significance ◽  
Surface Fluxes ◽  
Maximum Temperature ◽  
Seasonal Forecasts ◽  
La Plata ◽  
La Plata Basin ◽  
Surface Climate ◽  
Soil Moisture Initialization

Abstract This work examines the evolution of soil moisture initialization biases and their effects on seasonal forecasts depending on the season and vegetation type for a regional model over the La Plata basin in South America. WRF–Noah simulations covering multiple cases during a 2-yr period are designed to emphasize the conceptual nature of the simulations at the expense of the statistical significance of the results. Analysis of the surface climate shows that the seasonal predictive skill is higher when the model is initialized during the wet season and the initial soil moisture differences are small. Large soil moisture biases introduce large surface temperature biases, particularly for savanna, grassland, and cropland vegetation covers at any time of the year, thus introducing uncertainty in the surface climate. Regions with evergreen broadleaf forest have roots that extend to the deep layer whose moisture content affects the surface temperature through changes in the partitioning of the surface fluxes. The uncertainties of monthly maximum temperature can reach several degrees Celsius during the dry season in cases when 1) the soil is much wetter in the reanalysis than in the WRF–Noah equilibrium soil moisture and 2) the memory of the initial value is long because of scarce rainfall and low temperatures. This study suggests that responses of the atmosphere to soil moisture initialization depend on how the initial wet and dry conditions are defined, stressing the need to take into account the characteristics of a particular region and season when defining soil moisture initialization experiments.

INTER-SEASONAL AND INTER-BASINS HYDROLOGICAL COUPLING IN SOUTH AMERICA

2021 ◽  
Author(s):  
Paulo Rodrigo Zanin ◽  
Prakki Satyamurty
Keyword(s):  
Soil Moisture ◽  
Amazon Basin ◽  
Winter Season ◽  
Western Region ◽  
South American ◽  
La Plata ◽  
La Plata Basin ◽  
Precipitation Recycling ◽  
Source Sink ◽  
Southeastern Region

AbstractThe inter-seasonal and inter-basins hydrological couplings between the Amazon and the La Plata basins are obtained with the help of ERA-5 atmospheric reanalysis, MERGE/CPTEC precipitation, GLEAM evapotranspiration and the GLDAS/Noah soil moisture datasets. The hypotheses formulated by Zanin and Satyamurty (2020a) about the hydrological processes interconnecting the Amazon Basin and the La Plata Basin are tested. A new method for finding the source-sink relationships among the boxes (regions) is presented. The precipitation recycling, frequency of source-sink behaviors, the soil moisture memory and the continental moisture transport between remote regions are evaluated. The main result of this study is that the amount of water precipitated over the Southeastern region of the Amazon Basin at the end of the South American Monsoon during autumn season, influences the amount of precipitation during winter season over the Central-western region of the La Plata Basin.

How Much Do Different Land Models Matter for Climate Simulation? Part I: Climatology and Variability

2010 ◽  
Vol 23 (11) ◽  
pp. 3120-3134 ◽  
Author(s):  
Jiangfeng Wei ◽  
Paul A. Dirmeyer ◽  
Zhichang Guo ◽  
Li Zhang ◽  
Vasubandhu Misra
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Latent Heat ◽  
General Circulation ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Time Step ◽  
The Impact

Abstract An atmospheric general circulation model (AGCM) is coupled to three different land surface schemes (LSSs), both individually and in combination (i.e., the LSSs receive the same AGCM forcing each time step and the averaged upward surface fluxes are passed back to the AGCM), to study the uncertainty of simulated climatologies and variabilities caused by different LSSs. This tiling of the LSSs is done to study the uncertainty of simulated mean climate and climate variability caused by variations between LSSs. The three LSSs produce significantly different surface fluxes over most of the land, no matter whether they are coupled individually or in combination. Although the three LSSs receive the same atmospheric forcing in the combined experiment, the inter-LSS spread of latent heat flux can be larger or smaller than the individually coupled experiment, depending mostly on the evaporation regime of the schemes in different regions. Differences in precipitation are the main reason for the different latent heat fluxes over semiarid regions, but for sensible heat flux, the atmospheric differences and LSS differences have comparable contributions. The influence of LSS uncertainties on the simulation of surface temperature is strongest in dry seasons, and its influence on daily maximum temperature is stronger than on minimum temperature. Land–atmosphere interaction can dampen the impact of LSS uncertainties on surface temperature in the tropics, but can strengthen their impact in middle to high latitudes. Variations in the persistence of surface heat fluxes exist among the LSSs, which, however, have little impact on the global pattern of precipitation persistence. The results provide guidance to future diagnosis of model uncertainties related to LSSs.

scholarly journals Impacts of Irrigation on Summertime Temperatures in the Pacific Northwest

2020 ◽  
Vol 24 (1) ◽  
pp. 1-26
Author(s):  
Patricia M. Lawston ◽  
Joseph A. Santanello ◽  
Brian Hanson ◽  
Kristi Arsensault
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Surface Temperature ◽  
Land Surface ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Climate Signal ◽  
Near Surface ◽  
Surface Temperatures ◽  
Land Surface Temperatures

AbstractIrrigation has the potential to modify local weather and regional climate through a repartitioning of water among the surface, soil, and atmosphere with the potential to drastically change the terrestrial energy budget in agricultural areas. This study uses local observations, satellite remote sensing, and numerical modeling to 1) explore whether irrigation has historically impacted summer maximum temperatures in the Columbia Plateau, 2) characterize the current extent of irrigation impacts to soil moisture (SM) and land surface temperature (LST), and 3) better understand the downstream extent of irrigation’s influence on near-surface temperature, humidity, and boundary layer development. Analysis of historical daily maximum temperature (TMAX) observations showed that the three Global Historical Climate Network (GHCN) sites downwind of Columbia Basin Project (CBP) irrigation experienced statistically significant cooling of the mean summer TMAX by 0.8°–1.6°C in the post-CBP (1968–98) as compared to pre-CBP expansion (1908–38) period, opposite the background climate signal. Remote sensing observations of soil moisture and land surface temperatures in more recent years show wetter soil (~18%–25%) and cooler land surface temperatures over the irrigated areas. Simulations using NASA’s Land Information System (LIS) coupled to the Weather Research and Forecasting (WRF) Model support the historical analysis, confirming that under the most common summer wind flow regime, irrigation cooling can extend as far downwind as the locations of these stations. Taken together, these results suggest that irrigation expansion may have contributed to a reduction in summertime temperatures and heat extremes within and downwind of the CBP area. This supports a regional impact of irrigation across the study area.

scholarly journals Experiments using new initial soil moisture conditions and soil map in the Eta model over La Plata Basin

2013 ◽  
Vol 121 (3-4) ◽  
pp. 119-136 ◽  
Author(s):  
Moira E. Doyle ◽  
Javier Tomasella ◽  
Daniel A. Rodriguez ◽  
Sin Chan Chou
Keyword(s):  
Soil Moisture ◽  
La Plata ◽  
Soil Map ◽  
Initial Soil Moisture ◽  
La Plata Basin ◽  
Initial Soil ◽  
Eta Model ◽  
Moisture Conditions

scholarly journals Droughts and Floods in the La Plata Basin in Soil Moisture Data and GRACE

2015 ◽  
Vol 7 (6) ◽  
pp. 7324-7349 ◽  
Author(s):  
Sarah Abelen ◽  
Florian Seitz ◽  
Rodrigo Abarca-del-Rio ◽  
Andreas Güntner
Keyword(s):  
Soil Moisture ◽  
La Plata ◽  
Soil Moisture Data ◽  
La Plata Basin ◽  
Droughts And Floods

scholarly journals Impact of Soil Moisture Initialization in the Simulation of Indian Summer Monsoon Using RegCM4

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1148
Author(s):  
Suman Maity ◽  
Sridhara Nayak ◽  
Kuvar Satya Singh ◽  
Hara Prasad Nayak ◽  
Soma Dutta
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Surface Temperature ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Careful Examination ◽  
Soil Moisture Data ◽  
Statistical Measures ◽  
The Impact ◽  
Soil Moisture Initialization

Soil moisture is one of the key components of land surface processes and a potential source of atmospheric predictability that has received little attention in regional scale studies. In this study, an attempt was made to investigate the impact of soil moisture on Indian summer monsoon simulation using a regional model. We conducted seasonal simulations using a regional climate model (RegCM4) for two different years, viz., 2002 (deficit) and 2011 (normal). The model was forced to initialize with the high-resolution satellite-derived soil moisture data obtained from the Climate Change Initiative (CCI) of the European Space Agency (ESA) by replacing the default static soil moisture. Simulated results were validated against high-resolution surface temperature and rainfall analysis datasets from the India Meteorology Department (IMD). Careful examination revealed significant advancement in the RegCM4 simulation when initialized with soil moisture data from ESA-CCI despite having regional biases. In general, the model exhibited slightly higher soil moisture than observation, RegCM4 with ESA setup showed lower soil moisture than the default one. Model ability was relatively better in capturing surface temperature distribution when initialized with high-resolution soil moisture data. Rainfall biases over India and homogeneous regions were significantly improved with the use of ESA-CCI soil moisture data. Several statistical measures such as temporal correlation, standard deviation, equitable threat score (ETS), etc. were also employed for the assessment. ETS values were found to be better in 2011 and higher in the simulation with the ESA setup. However, RegCM4 was still unable to enhance its ability in simulating temporal variation of rainfall adequately. Although initializing with the soil moisture data from the satellite performed relatively better in a normal monsoon year (2011) but had limitations in simulating different epochs of monsoon in an extreme year (2002). Thus, the study concluded that the simulation of the Indian summer monsoon was improved by using RegCM4 initialized with high-resolution satellite soil moisture data although having limitations in predicting temporal variability. The study suggests that soil moisture initialization has a critical impact on the accurate prediction of atmospheric circulation processes and convective rainfall activity.

scholarly journals Surface Circulation Types and Daily Maximum and Minimum Temperatures in Southern La Plata Basin

2013 ◽  
Vol 52 (11) ◽  
pp. 2450-2459 ◽  
Author(s):  
Olga Clorinda Penalba ◽  
María Laura Bettolli ◽  
Pablo Andrés Krieger
Keyword(s):  
Heat Waves ◽  
Extreme Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
La Plata ◽  
Circulation Types ◽  
La Plata Basin ◽  
Surface Circulation

AbstractLa Plata basin is one of the most important agricultural and hydropower-producing regions in the world. Extreme climate events such as cold and heat waves and frost events have a significant socioeconomic impact. This work analyzes the influence of the surface circulation in southern South America on daily maximum temperature TMAX and daily minimum temperature TMIN in southern La Plata basin. A Z test for the comparison of mean values and a Kolmogorov–Smirnov test for the comparison of distributions of TMAX and TMIN associated with each circulation pattern were performed. Specific daily surface circulation types are found to contribute to TMAX and TMIN anomalies and to have a predominant occurrence in the development of the extreme temperature events in the region. The TMAX spatial response to the regional low-level circulation is more homogenous and extended than is the response of TMIN.

scholarly journals Climate Change Dry Spell Impact on Agriculture in Salyantar, Dhading, Central Nepal

2016 ◽  
Vol 16 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Pramila Paudyal ◽  
Dinesh Raj Bhuju ◽  
Manoj Aryal
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Statistical Significance ◽  
Maximum Temperature ◽  
Trend Test ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Central Nepal ◽  
Dry Spell ◽  
The Impact

Understanding the problem increasingly posed by climatic change is one of the critical challenges of our time. A study was carried out in Salyantar village in Dhading district of central Nepal to understand and assess the extent of climate change impacts on agriculture. The impact assessment was performed through analysis of meteorological data, Landsat images, and people’s perception on changes relative to agriculture sector. Mann-Kendall statistical trend test was used to assign statistical significance to the trend whereas temperature vegetation dryness index (TVDI) was used to identify soil moisture condition as an assessment criterion. The perception of local people on climate change and its impacts was studied through generalized questionnaire survey and participatory rural appraisal. The results of the study portrayed rise in temperature in the study area in the recent years in comparison to the past. The maximum temperature increment was 0.03p C per year. As for precipitation, it showed decreasing trend by 1.855mm per year. The TVDI obtained from Landsat image, showed decreasing trend of soil moisture in different years, which indicate an increased longer dry spell. This has unswerving effect on agriculture as the entire Salyantar village is dependent upon rain-fed agriculture. The perceived impacts on agriculture were decreased crop yield, reduced soil moisture, and increased incidence of new pests and invasive plant species. Such impacts were fairly heterogeneous in distribution. The Salyantar village, a raised flat-land of river deposition already stuck in the grip of water stress, was found exacerbated by the effect of climate change.Nepal Journal of Science and Technology Vol. 16, No.1 (2015) pp.59-68

Contribution of cold fronts to seasonal rainfall in simulations over the southern La Plata Basin

2016 ◽  
Vol 68 (2-3) ◽  
pp. 243-255 ◽  
Author(s):  
EM de Jesus ◽  
RP da Rocha ◽  
MS Reboita ◽  
M Llopart ◽  
LM Mosso Dutra ◽  
...  
Keyword(s):  
Seasonal Rainfall ◽  
La Plata ◽  
Cold Fronts ◽  
La Plata Basin
Sign in / Sign up

Export Citation Format

Share Document