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Natural resources are gradually coming under continuous and increasing pressure due to anthropogenic interventions and climate variabilities. The result of these pressures is reflected in the sustainability of natural resources. Significant scientific efforts during the recent years focus on mitigating the effects of these pressures and on increasing the sustainability of natural resources. Hence, there is a need to develop specific indices and indicators that will reveal the areas having the highest risks. The Water and Land Resources Degradation Index (WLDI) was developed for this purpose. WLDI consists of eleven indicators and its outcome results from the spatiotemporal performance of these indicators. The WLDI is based on the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). The WLDI is applied for the period from October 1983 to September 1996, considering Greece as a study area. The results of the application of this index reveal the areas with the highest risks, especially in the agricultural sector, with less than the needed water quantities due to extensive periods of droughts. This index could be used by scientists, but also by policy makers, to better and more sustainably manage environmental pressures.
Demetrios E. Tsesmelis; Christos A. Karavitis; Kleomenis Kalogeropoulos; Andreas Tsatsaris; Efthimios Zervas; Constantina G. Vasilakou; Nikolaos Stathopoulos; Nikolaos A. Skondras; Stavros G. Alexandris; Christos Chalkias; Constantinos Kosmas. Development and Application of Water and Land Resources Degradation Index (WLDI). Earth 2021, 2, 515 -531.
AMA StyleDemetrios E. Tsesmelis, Christos A. Karavitis, Kleomenis Kalogeropoulos, Andreas Tsatsaris, Efthimios Zervas, Constantina G. Vasilakou, Nikolaos Stathopoulos, Nikolaos A. Skondras, Stavros G. Alexandris, Christos Chalkias, Constantinos Kosmas. Development and Application of Water and Land Resources Degradation Index (WLDI). Earth. 2021; 2 (3):515-531.
Chicago/Turabian StyleDemetrios E. Tsesmelis; Christos A. Karavitis; Kleomenis Kalogeropoulos; Andreas Tsatsaris; Efthimios Zervas; Constantina G. Vasilakou; Nikolaos Stathopoulos; Nikolaos A. Skondras; Stavros G. Alexandris; Christos Chalkias; Constantinos Kosmas. 2021. "Development and Application of Water and Land Resources Degradation Index (WLDI)." Earth 2, no. 3: 515-531.
Estimated Reference Evapotranspiration (ETo), requires the meteorological attributes to be taken above standardized well-watered and vegetation-covered surfaces. However, worldwide such vegetation-reference sites are not common. This results in mistaken estimates of ETo by using the well-known and extensively applied FAO-56 Penman–Monteith formula. Consequently, the use of inappropriate data for ETo estimation from non-ideal surfaces, leads to significant and systematic cumulative errors introducing uncertainties when determining the crop water requirements in a region. Additionally, the existing climatic stations are not spatially distributed but rather concentrated mostly in non-rural urban areas or in local airports, operating above non–standardized surfaces. The purpose of this work is to assess the effect of using daily meteorological data recorded above a well-watered short crop compared to data obtained above dry bare soil, at the same local environment, using two widely used ETo models: the ASCE Penman-Monteith and the Hargreaves-Samani. The results indicate that the meteorological conditions above the different surfaces are quite different, presenting higher temperature and lower relative humidity values above the bare soil surface compared to the well-watered short crop and resulting, finally, to errors in the estimation of reference evapotranspiration. These errors appear to enhance as air temperature, vapor pressure deficit, radiation and atmospheric clearness increases, or relative humidity decreases but are diminishing under adequate soil moisture conditions resulting after rainfall events. The ETo differences vary according to the model each time adopted but the soil substrate influence can be detected by more sophisticated methods, such as FAO56-PM, which consider the energy balance of the surface.
Stavros Alexandris; Nikolaos Proutsos. How significant is the effect of the surface characteristics on the Reference Evapotranspiration estimates? Agricultural Water Management 2020, 237, 106181 .
AMA StyleStavros Alexandris, Nikolaos Proutsos. How significant is the effect of the surface characteristics on the Reference Evapotranspiration estimates? Agricultural Water Management. 2020; 237 ():106181.
Chicago/Turabian StyleStavros Alexandris; Nikolaos Proutsos. 2020. "How significant is the effect of the surface characteristics on the Reference Evapotranspiration estimates?" Agricultural Water Management 237, no. : 106181.
A new empirical equation for the estimation of daily dry above ground biomass (D-AGB) for a hybrid of soybean (Glycine max L.) is proposed. This equation requires data for three crop dependent parameters; leaf area index, plant height, and cumulative crop evapotranspiration. Bilinear surface regression analysis was used in order to estimate the factors entering in the empirical model. For the calibration of the proposed model, data yielded from a well-watered soybean crop for the year 2015, in the experimental field (0.1 ha) of the agricultural University of Athens, were used as a reference. Verification of the validity of the model was obtained by using data from a 2014 cultivation period for well-watered soybean cultivation (100% of crop evapotranspiration water treatment), as well as data from three irrigation treatments (75%, 50%, 25% of crop evapotranspiration) for two cultivation periods (2014–2015). The proposed method for the estimation of D-AGB may be proven as a useful tool for estimations without using destructive sampling.
Christos Vamvakoulas; Stavros Alexandris; Ioannis Argyrokastritis. Dry Above Ground Biomass for a Soybean Crop Using an Empirical Model in Greece. Energies 2020, 13, 201 .
AMA StyleChristos Vamvakoulas, Stavros Alexandris, Ioannis Argyrokastritis. Dry Above Ground Biomass for a Soybean Crop Using an Empirical Model in Greece. Energies. 2020; 13 (1):201.
Chicago/Turabian StyleChristos Vamvakoulas; Stavros Alexandris; Ioannis Argyrokastritis. 2020. "Dry Above Ground Biomass for a Soybean Crop Using an Empirical Model in Greece." Energies 13, no. 1: 201.
The degradation of natural resources at an intense rate creates serious problems in the environmental systems particularly with the compounding effects of climatic vagaries and changes. On the one hand, desertification is a crucial universal, mostly an anthropogenic environmental issue affecting soils all over the world. On the other hand, drought is a natural phenomenon in direct association with reduced rainfall in various spatial and temporal frames. Vulnerabilities to drought and desertification are complex processes caused by environmental, ecological, social, economic and anthropogenic factors. Particularly for the Mediterranean semi-arid conditions, where the physical and structural systems are more vulnerable, the abuse and overuse of the natural resources lead to their degradation and ultimately, if the current trends continue, to their marginalization. The scope of the current effort is trying to find any common drivers for the pressures of both processes. Thus, the vulnerabilities to drought and desertification are comparing by using the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). The indices are calculated from October 1983 to September 1996 in Greece. Greece is prone to desertification and it is often experiencing intense droughts, thus it presents an almost ideal case study area. The results may indicate that the most important factor for such procedures is the deficits in water resources, either due to lower than usually expected rainfall or to higher societal water demand.
Demetrios E. Tsesmelis; Christos A. Karavitis; Panagiotis D. Oikonomou; Stavros Alexandris; Constantinos Kosmas. Assessment of the Vulnerability to Drought and Desertification Characteristics Using the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). Resources 2018, 8, 6 .
AMA StyleDemetrios E. Tsesmelis, Christos A. Karavitis, Panagiotis D. Oikonomou, Stavros Alexandris, Constantinos Kosmas. Assessment of the Vulnerability to Drought and Desertification Characteristics Using the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI). Resources. 2018; 8 (1):6.
Chicago/Turabian StyleDemetrios E. Tsesmelis; Christos A. Karavitis; Panagiotis D. Oikonomou; Stavros Alexandris; Constantinos Kosmas. 2018. "Assessment of the Vulnerability to Drought and Desertification Characteristics Using the Standardized Drought Vulnerability Index (SDVI) and the Environmentally Sensitive Areas Index (ESAI)." Resources 8, no. 1: 6.
The main premise of the current effort is that the use of a drought index, such as Standardized Precipitation Index (SPI), may lead to a more appropriate understanding of drought duration, magnitude and spatial extent in semi-arid areas like Greece. The importance of the Index may be marked in its simplicity and its ability to identify the beginning and end of a drought event. Thus, it may point towards drought contingency planning and through it to drought alert mechanisms. In this context, Greece, as it very often faces the hazardous impacts of droughts, presents an almost ideal case for the SPI application. The present approach examines the SPI drought index application for all of Greece and it is evaluated accordingly by historical precipitation data. Different time series of data from 46 precipitation stations, covering the period 1947–2004, and for time scales of 1, 3, 6, 12 and 24 months, were used. The computation of the index was achieved by the appropriate usage of a pertinent software tool. Then, spatial representation of the SPI values was carried out with geo-statistical methods using the SURFER 9 software package. The results underline the potential that the SPI usage exhibits in a drought alert and forecasting effort as part of a drought contingency planning posture.
Christos A. Karavitis; Stavros Alexandris; Demetrios E. Tsesmelis; George Athanasopoulos. Application of the Standardized Precipitation Index (SPI) in Greece. Water 2011, 3, 787 -805.
AMA StyleChristos A. Karavitis, Stavros Alexandris, Demetrios E. Tsesmelis, George Athanasopoulos. Application of the Standardized Precipitation Index (SPI) in Greece. Water. 2011; 3 (3):787-805.
Chicago/Turabian StyleChristos A. Karavitis; Stavros Alexandris; Demetrios E. Tsesmelis; George Athanasopoulos. 2011. "Application of the Standardized Precipitation Index (SPI) in Greece." Water 3, no. 3: 787-805.