scholarly journals Estimation of evapotranspiration rate by using the Penman–Monteith and Hargreaves formulas for the loess in Northeast Bulgaria complex with HYDRUS-1D

2019 ◽  
Vol 48 (3) ◽  
pp. 3-9
Author(s):  
Peter Gerginov ◽  
Dimitar Antonov
Keyword(s):  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Danube River ◽  
Near Surface ◽  
The North ◽  
Evapotranspiration Rate ◽  
Scientific Project ◽  
Unsaturated Zones ◽  
The Impact ◽  
Hydrus 1D

Loess and loess-like sediments cover approximately 13% of the Bulgarian territory, mainly within the Danubian plain. From the Danube River to the Fore-Balkan, the loess soils form a loess complex where its depth varies from 50–60 meters in the north to few meters in the south, respectively. Widespread loess sediments possess a specific feature: they typically form deep unsaturated zones. Quantification of the near surface water balance is extremely important for evaluating land-atmosphere interactions, and the impact of land-use change on the subsurface flow and the evapotranspiration rate is an essential term in this quantification. In the frames of a scientific project, an automatic weather station was installed in a typical plain terrain of the loess complex in Northeast Bulgaria, recording meteorological data from September 2015 to February 2017. This study provides a mathematical description of processes (i.e., Penman-Monteith and Hargreaves Methods) used to estimate daily evapotranspiration rates implemented into the numerical model HYDRUS-1D, as well as a respective rate investigation of months with and without intensive rainfalls. Overall results indicate that using the Hargreaves formula for evaluation of the potential evapotranspiration leads to overestimation between 10% and 20%, respectively for a “wet” and “dry” month.

scholarly journals Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D

2012 ◽  
Vol 16 (8) ◽  
pp. 2485-2497 ◽  
Author(s):  
B. Leterme ◽  
D. Mallants ◽  
D. Jacques
Keyword(s):  
Water Balance ◽  
Groundwater Recharge ◽  
Potential Evapotranspiration ◽  
Future Climate ◽  
Annual Precipitation ◽  
Balance Model ◽  
Subtropical Climate ◽  
Northern Spain ◽  
Near Surface ◽  
Hydrus 1D

Abstract. The sensitivity of groundwater recharge to different climate conditions was simulated using the approach of climatic analogue stations, i.e. stations presently experiencing climatic conditions corresponding to a possible future climate state. The study was conducted in the context of a safety assessment of a future near-surface disposal facility for low and intermediate level short-lived radioactive waste in Belgium; this includes estimation of groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richards based soil water balance model HYDRUS-1D and meteorological time series from analogue stations. This study used four analogue stations for a warmer subtropical climate with changes of average annual precipitation and potential evapotranspiration from −42% to +5% and from +8% to +82%, respectively, compared to the present-day climate. Resulting water balance calculations yielded a change in groundwater recharge ranging from a decrease of 72% to an increase of 3% for the four different analogue stations. The Gijon analogue station (Northern Spain), considered as the most representative for the near future climate state in the study area, shows an increase of 3% of groundwater recharge for a 5% increase of annual precipitation. Calculations for a colder (tundra) climate showed a change in groundwater recharge ranging from a decrease of 97% to an increase of 32% for four different analogue stations, with an annual precipitation change from −69% to −14% compared to the present-day climate.

Towards a better assessment of the historical climate of Extremadura region (SW Spain)

2020 ◽  
Author(s):  
José Manuel Vaquero ◽  
María Cruz Gallego ◽  
Víctor M. S. Carrasco ◽  
Nieves Bravo-Paredes ◽  
María Ángeles Obregón ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Main Task ◽  
Winter Climate ◽  
Historical Climate ◽  
The North ◽  
Nao Index ◽  
Dry Conditions ◽  
Good Proxy ◽  
The North Atlantic Oscillation ◽  
The Impact

<p>Our efforts to a better understanding of the historical climate of the region of Extremadura (interior of the SW Iberia) have been directed in two main aspects. First, we have tried to recover all the meteorological data of the pre-instrumental period. Second, we have been working on the localization and analysis of proxy data, including “pro-pluvia” rogation ceremonies and a chronology of catastrophic floods in this region.</p><p>The recovery of historical meteorological data from libraries and archives and the subsequent digitization to obtain readable-machine version has been a main task in our research. Meteorological data from different sources (manuscripts, books, newspapers, etc.) and eight different locations in Extremadura have been recovered and digitized. The oldest data were read in 1824 (Fernández-Fernández et al., 2014). Other important meteorological series can be highlighted as the actinometric measurements in Cáceres for the period 1913-1920 (Bravo-Paredes et al., 2019).</p><p>“Pro-pluvia” rogations were celebrated during dry conditions to ask God for rain. In our case, 35 “pro-pluvia” rogations were retrieved for the period 1824-1931 from different locations in Extremadura. The winter climate of this region is strongly dominated by the North Atlantic Oscillation (NAO) and, therefore, these pro-pluvia rogations were associated to the NAO index to analyze this relationship. The results of our analysis show that the rogation ceremonies in Extremadura can be considered a good proxy for the NAO index. Also, it is important to know the magnitude and the impact of the catastrophic floods occurred in Extremadura. In total, 40 floods occurred in Badajoz were recovered from different documentary sources for the period 1545-1989.</p><p>All these research efforts will allow for a better understanding of the past climate in the region of Extremadura, where such studies have been very scarce.</p><p>References</p><p>Bravo-Paredes, N. et al. (2019) “Analysis of actinometric measurements under different sky conditions in Cáceres (Spain) for the period 1913-1920” Tellus B 71, 1663597. DOI: 10.1080/16000889.2019.1663597</p><p>Fernández-Fernández, M.I. et al. (2014) "The climate of Zafra from 1750 to 1840: History and description of weather observations" Climatic Change 126, 107–118. (doi: 10.1007/s10584-014-1201-5)</p>

scholarly journals Calculation of meteorological water balance in Iraq

2020 ◽  
Vol 2 (1) ◽  
pp. 84-89
Author(s):  
Hussein Ilaibi Zamil Al-Sudani ◽  
Keyword(s):  
Water Balance ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Meteorological Station ◽  
Actual Evapotranspiration ◽  
North East ◽  
Crucial Component ◽  
Water Surplus ◽  
Main Components ◽  
The Impact

The hydrology section is divided into two main components, surface and groundwater. One of the most important outcomes in the water balance equation for any natural area or water body is Evapotranspiration and it is also a crucial component of the hydrologic cycle. Prediction of monthly evapotranspiration can be obtained depending on observed monthly average temperatures at a meteorological station in each year. Calculating of water balance in Iraq depending on meteorological data and Thornthwaite method was the aim of this research. Results of corrected potential evapotranspiration (PEc) obtained from applying Thornthwaite formula were compared with annual and monthly rainfall in thirty two meteorological station in order to estimate actual evapotranspiration (AE). The results showed that the annual summation of rainfall increased from south west towards north east according to the increasing ratio of rainfall due to the impact of Mediterranean climate condition on Iraq. Actual evapotranspiration depends directly on water excess during calculating water balance. Water surplus contour map indicates increased values towards north-east direction of Iraq, where water surplus depends directly on both rainfall and actual evapotranspiration.

scholarly journals The Impact of Large-Scale Orography on Northern Hemisphere Winter Synoptic Temperature Variability

2019 ◽  
Vol 32 (18) ◽  
pp. 5799-5814 ◽  
Author(s):  
Nicholas J. Lutsko ◽  
Jane Wilson Baldwin ◽  
Timothy W. Cronin
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
North American ◽  
Large Scale ◽  
Temperature Variability ◽  
Temperature Gradients ◽  
Northwest Pacific ◽  
Near Surface ◽  
The North ◽  
The Impact

Abstract The impact of large-scale orography on wintertime near-surface (850 hPa) temperature variability on daily and synoptic time scales (from days to weeks) in the Northern Hemisphere is investigated. Using a combination of theory, idealized modeling work, and simulations with a comprehensive climate model, it is shown that large-scale orography reduces upstream temperature gradients, in turn reducing upstream temperature variability, and enhances downstream temperature gradients, enhancing downstream temperature variability. Hence, the presence of the Rockies on the western edge of the North American continent increases temperature gradients over North America and, consequently, increases North American temperature variability. By contrast, the presence of the Tibetan Plateau and the Himalayas on the eastern edge of the Eurasian continent damps temperature variability over most of Eurasia. However, Tibet and the Himalayas also interfere with the downstream development of storms in the North Pacific storm track, and thus damp temperature variability over North America, by approximately as much as the Rockies enhance it. Large-scale orography is also shown to impact the skewness of downstream temperature distributions, as temperatures to the north of the enhanced temperature gradients are more positively skewed while temperatures to the south are more negatively skewed. This effect is most clearly seen in the northwest Pacific, off the east coast of Japan.

scholarly journals Comparison of daily potential evapotranspiration calculated by two procedures based on Penman-Monteith type equation

2013 ◽  
Vol 61 (2) ◽  
pp. 173-176 ◽  
Author(s):  
Hana Hlaváčiková ◽  
Viliam Novák
Keyword(s):  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Aerodynamic Resistance ◽  
Type Equation ◽  
Simulation Models ◽  
Estimation Methods ◽  
Net Radiation ◽  
Water Simulation ◽  
Reference Crop ◽  
Hydrus 1D

Abstract Paper presents comparison of the daily reference crop (grass vegetation cover) potential evapotranspiration results calculated by the two modifications of the Penman-Monteith type equation. The first modification was published in FAO recommendation (Allen at al., 1998), PM-FAO, the second is modification according to Budagovskiy (1964) and Novák (1995), PM-BN. Both are used in soil water simulation models HYDRUS-1D and GLOBAL. Calculations were performed for frost-free seasons of the years 2000-2009, using the meteorological station Gabčíkovo (South Slovakia) meteorological data and canopy characteristics. The results indicate significant differences in daily and seasonal potential evapotranspiration. Reasons for those differences are discussed; they should be in different net radiation and aerodynamic resistance estimation methods.

scholarly journals The Basic Ingredients of the North Atlantic Storm Track. Part II: Sea Surface Temperatures

2011 ◽  
Vol 68 (8) ◽  
pp. 1784-1805 ◽  
Author(s):  
David James Brayshaw ◽  
Brian Hoskins ◽  
Michael Blackburn
Keyword(s):  
North Atlantic ◽  
Gulf Stream ◽  
Storm Track ◽  
Horizontal Wind ◽  
Near Surface ◽  
Continental Scale ◽  
The North ◽  
The North Atlantic ◽  
The Impact ◽  
Sst Gradient

Abstract The impact of North Atlantic SST patterns on the storm track is investigated using a hierarchy of GCM simulations using idealized (aquaplanet) and “semirealistic” boundary conditions in the atmospheric component (HadAM3) of the third climate configuration of the Met Office Unified Model (HadCM3). This framework enables the mechanisms determining the tropospheric response to North Atlantic SST patterns to be examined, both in isolation and in combination with continental-scale landmasses and orography. In isolation, a “Gulf Stream” SST pattern acts to strengthen the downstream storm track while a “North Atlantic Drift” SST pattern weakens it. These changes are consistent with changes in the extratropical SST gradient and near-surface baroclinicity, and each storm-track response is associated with a consistent change in the tropospheric jet structure. Locally enhanced near-surface horizontal wind convergence is found over the warm side of strengthened SST gradients associated with ascending air and increased precipitation, consistent with previous studies. When the combined SST pattern is introduced into the semirealistic framework (including the “North American” continent and the “Rocky Mountains”), the results suggest that the topographically generated southwest–northeast tilt in the North Atlantic storm track is enhanced. In particular, the Gulf Stream shifts the storm track south in the western Atlantic whereas the strong high-latitude SST gradient in the northeastern Atlantic enhances the storm track there.

scholarly journals Quantification of the radiative impact of light-absorbing particles during two contrasted snow seasons at Col du Lautaret (2058 m a.s.l., French Alps)

2020 ◽  
Vol 14 (12) ◽  
pp. 4553-4579
Author(s):  
François Tuzet ◽  
Marie Dumont ◽  
Ghislain Picard ◽  
Maxim Lamare ◽  
Didier Voisin ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Meteorological Data ◽  
Measurement Techniques ◽  
Temporal Variations ◽  
Surface Energy Budget ◽  
Near Surface ◽  
French Alps ◽  
Snow Season ◽  
Snow Metamorphism ◽  
The Impact

Abstract. The presence of light-absorbing particles (LAPs) in snow leads to a decrease in short-wave albedo affecting the surface energy budget. However, the understanding of the impacts of LAPs is hampered by the lack of dedicated datasets, as well as the scarcity of models able to represent the interactions between LAPs and snow metamorphism. The present study aims to address both these limitations by introducing a survey of LAP concentrations over two snow seasons in the French Alps and an estimation of their impacts based on the Crocus snowpack model that represents the complex interplays between LAP dynamics and snow metamorphism. First, a unique dataset collected at Col du Lautaret (2058 m a.s.l., above sea level, French Alps) for the two snow seasons 2016–2017 and 2017–2018 is presented. This dataset consists of spectral albedo measurements, vertical profiles of snow specific surface area (SSA), density and concentrations of different LAP species. Spectral albedos are processed to estimate SSA and LAP absorption-equivalent concentrations near the surface of the snowpack. These estimates are then compared to chemical measurements of LAP concentrations and SSA measurements. Our dataset highlights, among others, large discrepancies between two measurement techniques of black carbon (BC) concentrations in snow (namely thermal-optical and laser-induced incandescence). Second, we present ensemble snowpack simulations of the multi-physics version of the detailed snowpack model Crocus, forced with in situ meteorological data, as well as dust and BC deposition fluxes from an atmospheric model. The temporal variations of near-surface LAP concentrations and SSA are most of the time correctly simulated. The simulated seasonal radiative forcing of LAPs is 33 % higher for the 2017–2018 snow season than for the 2016–2017 one, highlighting a strong variability between these two seasons. However, the shortening of the snow season caused by LAPs is similar with 10 ± 5 and 11 ± 1 d for the first and the second snow seasons, respectively. This counter-intuitive result is attributed to two small snowfalls at the end of the first season and highlights the importance in accounting for meteorological conditions to correctly predict the impact of LAPs. The strong variability of season shortening caused by LAPs in the multi-physics ensemble for the first season (10 ± 5 d) also points out the sensitivity of model-based estimations of LAP impact on modelling uncertainties of other processes. Finally, the indirect impact of LAPs (i.e. the enhancement of energy absorption due to the acceleration of the metamorphism by LAPs) is negligible for the 2 years considered here, which is contrary to what was found in previous studies for other sites.

The Various Aspects of the Large- scale Atmospheric Circulation Response to the Northern Hemispheric Ocean Western Boundary Currents

2020 ◽  
Author(s):  
Nour-Eddine Omrani ◽  
Fumiaki Ogawa ◽  
Hisashi Nakamura ◽  
Noel Keenlyside ◽  
Sandro Lubis ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Western Boundary ◽  
Significant Implication ◽  
Western Boundary Currents ◽  
Near Surface ◽  
Boundary Currents ◽  
The North ◽  
The North Atlantic ◽  
The Impact

<p>Semi-idealized Atmospheric General Circulation-Model (AGCM) experiments are used, in order to study the different aspects of the hemisphere-scale wintertime troposphere/stratosphere-coupled circulation that are maintained by the North Atlantic and Pacific Ocean Western Boundary Currents (OWBCs). Here we show that the North Atlantic and Pacific OWBCs jointly maintain and shape the wintertime hemispheric circulation and its leading mode of variability Northern Annular Mode (NAM). The OWBCs energize baroclinic waves that reinforce quasi-annular hemispheric structure in the tropospheric eddy-driven jetstreams and NAM variability. Without the OWBCs, the wintertime NAM variability is much weaker and its impact on the continental and maritime surface climate is largely insignificant. Atmospheric energy redistribution caused by the OWBCs acts to damp the near-surface atmospheric baroclinicity and compensates the associated oceanic meridional energy transport in agreement with the Bjerknes compensation. Furthermore, the OWBCs substantially weaken the wintertime stratospheric polar vortex by enhancing the upward planetary wave propagation, and thereby affecting both stratospheric and tropospheric NAM-annularity. It is shown that the impact of OWBCs on northern hemisphere circulation has significant implication for stratosphere/troposphere dynamical coupling, time-scales on the NAM, frequency of Sudden stratospheric warming and potential formation of polar stratospheric clouds.</p><p> </p><p>Reference:</p><p>Omrani et al., 2019: Key Role of the ocean Western Boundary currents in shaping the Northern Hemisphere climate, Scientific Reports, https://doi.org/10.1038/s41598-019-39392-y</p><p> </p>

scholarly journals Assessing the Impact of a Future Volcanic Eruption on Decadal Predictions

2018 ◽  
Author(s):  
Sebastian Illing ◽  
Christopher Kadow ◽  
Holger Pohlmann ◽  
Claudia Timmreck
Keyword(s):  
Sea Ice ◽  
Volcanic Eruption ◽  
Volcanic Eruptions ◽  
Arctic Sea Ice ◽  
Climate System ◽  
The Arctic ◽  
Near Surface ◽  
The North ◽  
Precipitation Decrease ◽  
The Impact

Abstract. The likelihood of a large volcanic eruption in the future provides the largest uncertainty concerning the evolution of the climate system on the time scale of a few years; but also an excellent opportunity to learn about the behavior of the climate system, and our models thereof. So the question emerges how predictable is the response of the climate system to future eruptions? By this we mean, to what extent will the volcanic perturbation affect decadal climate predictions and how does the pre-eruption climate state influence the impact of the volcanic signal on the predictions? To address these questions, we performed decadal forecasts with the MiKlip prediction system in the low-resolution configuration for the initialization years 2012 and 2014, which differ in the Pacific Decadal Oscillation (PDO) phase among other things. Each forecast contains an artificial Pinatubo-like eruption starting in June of the first prediction year. For the construction of the aerosol radiative forcing, we used the global aerosol model ECHAM5-HAM in a version adapted for volcanic eruptions. We investigate the response of different climate variables, including near-surface air temperature, precipitation, frost days, and sea ice area fraction. Our results show that the average global cooling response over four years of about 0.2 K and the precipitation decrease of about 0.025 mm/day, is relatively robust throughout the different experiments and seemingly independent of the initialization state. However, on a regional scale, we find substantial differences between the initializations. The cooling effect in the North Atlantic and Europe lasts longer and the Arctic sea ice increase is stronger than in the simulations initialized in 2014. In contrast, the forecast initialized with a negative PDO shows a prolonged cooling in the North Pacific basin.

scholarly journals Regional characteristics of snowpacks related to avalanches in the central mountains of Japan

2013 ◽  
Vol 54 (62) ◽  
pp. 282-290
Author(s):  
Shinji Ikeda ◽  
Tomoyuki Noro
Keyword(s):  
Air Temperature ◽  
Snow Depth ◽  
Meteorological Data ◽  
The Sea Of Japan ◽  
Dominant Type ◽  
Near Surface ◽  
Regional Characteristics ◽  
The North ◽  
Diurnal Range ◽  
Study Sites

AbstractTo identify the regional characteristics of mountain snowpacks related to avalanches in the central mountains of Japan, snow-pit observations were carried out over a period of between two and five winters at six study sites in three major mountain ranges: the north, central and south alps. The relationship between snowpack characteristics and meteorological properties was then examined to suggest indicators that could determine the snowpack characteristics in the region using meteorological data. On the basis of the dominant type of persistent weakness found within snowpacks, the study sites were divided into three regions: (1) the mountains on the Sea of Japan side - the persistent weakness was caused mainly by the presence of melt-freeze crust (MFcr) layers; (2) the inland mountains - the persistent weakness was caused mainly by the presence of weak layers consisting of near-surface faceted crystals (FCsf); and (3) the mountains on the Pacific Ocean side - the persistent weakness was caused mainly by the formation of thick weak layers consisting of depth hoar (DH) near the ground. The results also suggest that certain meteorological elements are useful indicators of the tendency of a persistent weakness to form within the snowpack: (1) DH layers: TG (°C m−1) = |average air temperature |/average snow depth (notable weakness in DH layers is found in areas where the TG exceeds 10°C m−1, but in such areas rainfall prevents the development of DH layers); (2) FCsf layers: FCsf index (CC m) = average diurnal range of air temperature × snow depth (notable weakness in FCsf layers is found in areas where the FCsf index is ∼10°C m); (3) MFcr layers: MFcr index (day m) = number of days that exceed 0°C × snow depth (notable weakness in MFcr layers is found in areas where the MFcr index exceeds 40 day m).

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