scholarly journals Delineation of Dew Formation Zones in Iran Using Long-Term Model Simulations and Cluster Analysis

2021 ◽  
Author(s):  
Nahid Atashi ◽  
Dariush Rahimi ◽  
Victoria A. Sinclair ◽  
Martha A. Zaidan ◽  
Anton Rusanen ◽  
...  

Abstract. Dew is a non-conventional source of water that has been gaining interest over the last two decades, especially in arid and semi-arid regions. In this study, we performed a long-term (1979–2018) energy balance model simulation to estimate dew formation potential in Iran aiming to identify dew formation zones and to investigate the impacts of long-term variation in meteorological parameters on dew formation. The annual average of dew occurrence in Iran was ~ 102 days, with the lowest number of dewy days in summer (~ 7 days) and highest in winter (~ 45 days). The average daily dew yield was in the range of 0.03–0.14 L/m2 and the maximum was in the range of 0.29–0.52 L/m2. Six dew formation zones were identified based on cluster analysis of the timeseries of the simulated dew yield. The distribution of dew formation zones in Iran was closely aligned with topography and sources of moisture. Therefore, the coastal zones in the north and south of Iran (i.e., Caspian Sea and Oman Sea), showed the highest dew formation potential with 53 and 34 L/m2/year, whereas the dry interior regions (i.e., central Iran and the Lut Desert), with the average of 12–18 L/m2/year had the lowest potential for dew formation. Trend analysis results revealed a significance (p 

2021 ◽  
Vol 25 (9) ◽  
pp. 4719-4740
Author(s):  
Nahid Atashi ◽  
Dariush Rahimi ◽  
Victoria A. Sinclair ◽  
Martha A. Zaidan ◽  
Anton Rusanen ◽  
...  

Abstract. Dew is a non-conventional source of water that has been gaining interest over the last two decades, especially in arid and semi-arid regions. In this study, we performed a long-term (1979–2018) energy balance model simulation to estimate dew formation potential in Iran aiming to identify dew formation zones and to investigate the impacts of long-term variation in meteorological parameters on dew formation. The annual average of dew occurrence in Iran was ∼102 d, with the lowest number of dewy days in summer (∼7 d) and the highest in winter (∼45 d). The average daily dew yield was in the range of 0.03–0.14 L m−2 and the maximum was in the range of 0.29–0.52 L m−2. Six dew formation zones were identified based on cluster analysis of the time series of the simulated dew yield. The distribution of dew formation zones in Iran was closely aligned with topography and sources of moisture. Therefore, the coastal zones in the north and south of Iran (i.e., Caspian Sea and Oman Sea), showed the highest dew formation potential, with 53 and 34 L m−2 yr−1, whereas the dry interior regions (i.e., central Iran and the Lut Desert), with the average of 12–18 L m−2 yr−1, had the lowest potential for dew formation. Dew yield estimation is very sensitive to the choice of the heat transfer coefficient. The uncertainty analysis of the heat transfer coefficient using eight different parameterizations revealed that the parameterization used in this study – the Richards (2004) formulation – gives estimates that are similar to the average of all methods and are neither much lower nor much higher than the majority of other parameterizations and the largest differences occur for the very low values of daily dew yield. Trend analysis results revealed a significant (p<0.05) negative trend in the yearly dew yield in most parts of Iran during the last 4 decades (1979–2018). Such a negative trend in dew formation is likely due to an increase in air temperature and a decrease in relative humidity and cloudiness over the 40 years.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2463
Author(s):  
Nahid Atashi ◽  
Dariush Rahimi ◽  
Behnam Goortani ◽  
Jonathan Duplissy ◽  
Henri Vuollekoski ◽  
...  

Since water shortage has been a serious challenge in Iran, long-term investigations of alternative water resources are vital. In this study, we performed long-term (1979–2018) model simulation at seven locations (costal, desert, mountain, and urban conditions) in Iran to investigate temporal and spatial variation of dew formation. The model was developed to simulate the dew formation (water and ice) based on the heat and mass balance equation with ECMWF-ERA-Interim (European Centre for Medium-Range Weather Forecasts–Re-Analysis) meteorological data as input. According to the model simulation, the maximum mean yearly cumulative dew yield (~65 L/m2) was observed in the mountain region in the north part of Iran with a yearly mean cumulative dew yield was ~36 L/m2. The dew yield showed a clear seasonal variation at all selected locations with maximum yields in winter (mean monthly cumulative 3–8 L/m2 depending on the location). Here we showed that dew formation is frequent in northern Iran. In other areas, where there was suffering from water-stress (southern and central parts of Iran), dew can be a utilized as an alternative source of water. The dew yield during 2001–2014 was lower than the overall mean during the past 40 years a result of climate change in Iran.


2021 ◽  
Author(s):  
Nahid Atashi ◽  
Dariush Rahimi ◽  
Victoria A. Sinclair ◽  
Martha A. Zaidan ◽  
Anton Rusanen ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 641
Author(s):  
Michał Jasiński

Analysis of the connection between different units that operate in the same area assures always interesting results. During this investigation, the concerned area was a virtual power plant (VPP) that operates in Poland. The main distributed resources included in the VPP are a 1.25 MW hydropower plant and an associated 0.5 MW energy storage system. The mentioned VPP was a source of synchronic, long-term, multipoint power quality (PQ) data. Then, for five related measurement points, the conclusion about the relation in point of PQ was performed using correlation analysis, the global index approach, and cluster analysis. Global indicators were applied in place of PQ parameters to reduce the amount of analyzed data and to check the correlation between phase values. For such a big dataset, the occurrence of outliers is certain, and outliers may affect the correlation results. Thus, to find and exclude them, cluster analysis (k-means algorithm, Chebyshev distance) was applied. Finally, the correlation between PQ global indicators of different measurement points was performed. It assured general information about VPP units’ relation in point of PQ. Under the investigation, both Pearson’s and Spearman’s rank correlation coefficients were considered.


Fisheries ◽  
2020 ◽  
Vol 2020 (4) ◽  
pp. 44-51
Author(s):  
Aleksandr Zolotov ◽  
Nikolay Antonov ◽  
Olga Maznikova

The paper analyzes the long-term dynamics of stocks and annual catches of Pacific cod of the Kuril Islands, and also considers the structure of its modern fishery, taking into account the changes that have occurred in the organization of its coastal fishing in recent years. It was shown that the dynamics of commercial biomass of Pacific cod in the Northern and Southern Kuril Islands is comparable to that in 1975-2020 for groups in the southeastern part of the Bering Sea, the Karagin and Olyutor bays, on the shelf of Western Kamchatka, and in south-western Sakhalin. Development of the cod fishery in the North and South Kuril Islands in 1980-2019 went in accordance with the dynamics of stocks, the maximum catches were observed during the period of a high level of abundance of both groups in the 1980s. While the structure of the cod fishery on the shelf of the Northern Kuril Islands to date can be considered established, the development of fishing in the South Kuril Islands in the last two decades went by the gradual replacement of trawl fishing in the winter-spring period with snorkeling in the summer season.


Author(s):  
Vladimir A. Shabashev ◽  
◽  
Victor V. Barylnikov ◽  
Boris N. Medvedev ◽  
Valery A. Salikhov ◽  
...  
Keyword(s):  

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257869
Author(s):  
Jacoby Carter ◽  
Darren Johnson ◽  
Jeff Boundy ◽  
William Vermillion

To determine trends in either frog distribution or abundance in the State of Louisiana, we reviewed and analyzed frog call data from the Louisiana Amphibian Monitoring Program (LAMP). The data were collected between 1997 and 2017 using North American Amphibian Monitoring Program protocols. Louisiana was divided into three survey regions for administration and analysis: the Florida Parishes, and 2 areas west of the Florida parishes called North and South. Fifty-four routes were surveyed with over 12,792 stops and 1,066 hours of observation. Observers heard 26 species of the 31 species reported to be in Louisiana. Three of the species not heard were natives with ranges that did not overlap with survey routes. The other two species were introduced species, the Rio Grande Chirping Frog (Eleutherodactylus cystignathoides) and the Cuban Treefrog (Osteopilus septentrionalis). Both seem to be limited to urban areas with little to no route coverage. The 15 most commonly occurring species were examined in detail using the percentage of stops at which they observed along a given survey and their call indices. Most species exhibited a multimodal, concave, or convex pattern of abundance over a 15-year period. Among LAMP survey regions, none of the species had synchronous population trends. Only one group of species, winter callers, regularly co-occur. Based on the species lists, the North region could be seen as a subset of the South. However, based on relative abundance, the North was more similar to Florida parishes for both the winter and summer survey runs. Our analyses demonstrate that long-term monitoring (10 years or more) may be necessary to determine population and occupancy trends, and that frog species may have different local demographic patterns across large geographic areas.


2017 ◽  
Vol 8 (3) ◽  
pp. 801-815 ◽  
Author(s):  
Ute Daewel ◽  
Corinna Schrum

Abstract. Here we present results from a long-term model simulation of the 3-D coupled ecosystem model ECOSMO II for a North Sea and Baltic Sea set-up. The model allows both multi-decadal hindcast simulation of the marine system and specific process studies under controlled environmental conditions. Model results have been analysed with respect to long-term multi-decadal variability in both physical and biological parameters with the help of empirical orthogonal function (EOF) analysis. The analysis of a 61-year (1948–2008) hindcast reveals a quasi-decadal variation in salinity, temperature and current fields in the North Sea in addition to singular events of major changes during restricted time frames. These changes in hydrodynamic variables were found to be associated with changes in ecosystem productivity that are temporally aligned with the timing of reported regime shifts in the areas. Our results clearly indicate that for analysing ecosystem productivity, spatially explicit methods are indispensable. Especially in the North Sea, a correlation analysis between atmospheric forcing and primary production (PP) reveals significant correlations between PP and the North Atlantic Oscillation (NAO) and wind forcing for the central part of the region, while the Atlantic Multi-decadal Oscillation (AMO) and air temperature are correlated to long-term changes in PP in the southern North Sea frontal areas. Since correlations cannot serve to identify causal relationship, we performed scenario model runs perturbing the temporal variability in forcing condition to emphasize specifically the role of solar radiation, wind and eutrophication. The results revealed that, although all parameters are relevant for the magnitude of PP in the North Sea and Baltic Sea, the dominant impact on long-term variability and major shifts in ecosystem productivity was introduced by modulations of the wind fields.


Sign in / Sign up

Export Citation Format

Share Document