Prediction of climate change impacts on cotton yields in greece under eight climatic models using the aquacrop crop simulation model.

The impact of climate change on cotton yields in seven main arable crop sites in Greece (Agrinio, Alexandroupolis, Arta, Karditsa, Mikra, Pyrgos, Yliki) was investigated. The FAO AquaCrop (v.4) water driven model was used as a crop development simulation tool under eight climatic models (HadRM3, C4I, REMO MPI, ETHZ, CNRM, DMI-HIRHAM, KNMI, SMHI) based on IPPC’s A1B Climate Change scenario. The mean values of the models ensemble for temperature and precipitation were +1,8˚C until 2050 and +4 ˚C until the end of the century. The respective values for precipitation were -11% and -24%. The research was applied over three periods, 1961-1990, 2021-2050 and 2071-2099. AquaCrop validation for yield, biomass and canopy cover in respect to field data obtained from experiments carried out in Karditsa (Central Greece) from 2005 to 2007 was satisfactory on the account of Root Mean Square Error (0.17 to 0.49) and Index of Agreement (0.93 to 0.94). AquaCrop model was run using the Growing Degree Day mode in order to account better for the temperature variations. However, it gave erratic results for some specific climatic models (SMHI, KNMI, CNRM) in some years within the period 1961-1990. The predicted yields were highest in locations of western Greece (Agrinio, Arta, Pyrgos), whereas north-eastern Greece (Alexandroupolis) appeared to be less favoured by climate change. A tendency towards increasing yields by the end of the century was detected for the majority of the models. The efficiency of the eight models for yield predictions in the seven sites was assessed by means of a discriminant function analysis. On the account of their function coefficients over the seven sites, it was found that the models DMI and C4I explained consistently a great proportion of variation among the three time periods whereas the models ETHZ, SMHI and KNMI were more efficient in the periods 1961-1990, 2021-2050 and 2071-2099 respectively

Prediction of climate change impacts on cotton yields in greece under eight climatic models using the aquacrop crop simulation model [PRESENTATION]

The presentation includes the following sections: Introduction Previous research Materials and Method Climate scenario and models Crop simulation model Calibration and validation Future projections of some climatic parameters Cotton yield response to climate change Assessment of the used climatic models Comparison 2071-2100 and 1961-1990 Conclusions Acknowledgement

Detecting volcanic sulfur dioxide plumes in the Northern Hemisphere using the Brewer spectrophotometer, other networks, and satellite observations

This paper demonstrates that SO 2 columnar amounts have significantly increased following the five largest volcanic eruptions of the past decade in the Northern Hemisphere. A strong positive signal was detected by all the existing networks either ground based (Brewer, EARLINET, AirBase) or from satellites (OMI, GOME-2). The study particularly examines the adequacy of the existing Brewer network to detect SO 2 plumes of volcanic origin in comparison to other networks and satellite platforms. The comparison with OMI and 45 GOME-2 SO 2 space-borne retrievals shows statistically significant agreement between the Brewer network data and the collocated satellite overpasses. It is shown that the Brewer instrument is capable of detecting significant columnar SO 2 increases following large volcanic eruptions, when SO 2 levels rise well above the instrumental noise of daily observations, estimated to be of the order of 2 DU. A model exercise from the MACC project shows that the large increases of SO 2 over Europe following the Bárðarbunga eruption in Iceland were not caused by local sources or ship emissions but are clearly linked to the eruption. We propose that by combining Brewer data with that from other networks and satellites, a useful tool aided by trajectory analyses and modeling could be created which can be used to forecast high SO 2 values both at ground level and in air flight corridors following future eruptions

Ozone, DNA-active UV radiation, and cloud changes for the near-global mean and at high latitudes due to enhanced greenhouse gas concentrations

This study analyses the variability and trends of ultraviolet-B (UV-B, wavelength 280–320 nm) radiation that can cause DNA damage. The variability and trends caused by climate change due to enhanced greenhouse gas (GHG) concentrations. The analysis is based on DNA-active irradiance, total ozone, total cloud cover, and surface albedo calculations with the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) chemistry–climate model (CCM) free-running simulations following the RCP 6.0 climate scenario for the period 1960–2100. The model output is evaluated with DNA-active irradiance ground-based measurements, satellite SBUV (v8.7) total-ozone measurements, and satellite MODerate-resolution Imaging Spectroradiometer (MODIS) Terra cloud cover data. The results show that the model reproduces the observed variability and change in total ozone, DNA-active irradiance, and cloud cover for the period 2000–2018 quite well according to the statistical comparisons. Between 50∘ N–50∘ S, the DNA-damaging UV radiation is expected to decrease until 2050 and to increase thereafter, as was shown previously by Eleftheratos et al. (2020). This change is associated with decreases in the model total cloud cover and negative trends in total ozone after about 2050 due to increasing GHGs. The new study confirms the previous work by adding more stations over low latitudes and mid-latitudes (13 instead of 5 stations). In addition, we include estimates from high-latitude stations with long-term measurements of UV irradiance (three stations in the northern high latitudes and four stations in the southern high latitudes greater than 55∘). In contrast to the predictions for 50∘ N–50∘ S, it is shown that DNA-active irradiance will continue to decrease after the year 2050 over high latitudes because of upward ozone trends. At latitudes poleward of 55∘ N, we estimate that DNA-active irradiance will decrease by 8.2 %±3.8 % from 2050 to 2100. Similarly, at latitudes poleward of 55∘ S, DNA-active irradiance will decrease by 4.8 % ± 2.9 % after 2050. The results for the high latitudes refer to the summer period and not to the seasons when ozone depletion occurs, i.e. in late winter and spring. The contributions of ozone, cloud, and albedo trends to the DNA-active irradiance trends are estimated and discussed.</p

Estimation of climate change over Greece using climate models and downscaling methods

Βασικός σκοπός της παρούσας μελέτης ήταν η εκτίμηση των κλιματικών μεταβολών που αναμένεται να συμβούν στον ελληνικό χώρο με τη βοήθεια μοντέλων προσομοίωσης. Αρχικά μελετήθηκε η κλιματολογία της βροχόπτωσης και των συνιστωσών της στην ευρύτερη περιοχή της Μεσογείου (30οΒ-47οΒ και 10οΔ-40οΑ) και έγινε προσπάθεια να εκτιμηθούν για την περιοχή αυτή οι μεταβολές της βροχόπτωσης και των συνιστωσών της που θα προκύψουν ως συνέπεια της παγκόσμιας θέρμανσης. Η μελέτη κρίθηκε σκόπιμο να βασιστεί στα αποτελέσματα προσομοιώσεων από Μοντέλα Γενικής Κυκλοφορίας (GCMs). Πιο συγκεκριμένα χρησιμοποιούνται τα αποτελέσματα προσομοιώσεων εννέα GCMs (BCCR BCM2.0, CCCMA CGCM3.1, CNRM CM3, GFDL CM2.0, GISS ER, HAD CM3, IPCL CM4, MIROC MEDRES και MRI CGCM2) που διεξήχθησαν στα πλαίσια της 4ης Έκθεσης του IPCC (IPCC AR4). Αρχικά συγκρίθηκαν τα αποτελέσματα των πεδίων της συνολικής βροχόπτωσης που προκύπτουν από τις προσομοιώσεις των εννέα GCMs και του «μέσου μοντέλου» (ensemble mean) με τα πλεγματικά δεδομένα από παρατηρήσεις GPCP V2. Από τη σύγκριση προέκυψαν συνοπτικά τα ακόλουθα: · Το σύνολο των GCMs καθώς και το «μέσο μοντέλο» αναπαράγουν ικανοποιητικά τα γενικά χαρακτηριστικά της χωρικής κατανομής τόσο της συνολικής χειμερινής βροχόπτωσης όσο και της συνολικής θερινής βροχόπτωσης στην περιοχή της Μεσογείου. · Σε ορισμένες περιοχές η πλειονότητα των GCMs είτε υπερεκτιμά είτε υποεκτιμά σημαντικά τα ύψη της συνολικής βροχόπτωσης τόσο κατά το χειμώνα όσο και κατά τα θέρος. · Πιο συγκεκριμένα η πλειονότητα των GCMs υπερεκτιμά τα ύψη της συνολικής χειμερινής βροχόπτωσης στην Ιβηρική Χερσόνησο, και τα υποεκτιμά στην Ελλάδα και στην ευρύτερη περιοχή του Εύξεινου Πόντου. · Η πλειονότητα των GCMs υπερεκτιμά τα ύψη της συνολικής θερινής βροχόπτωσης στη Βορειοδυτική Αφρική, στη Βορειοανατολική Ιβηρική Χερσόνησο και στα Βόρεια Βαλκάνια. Στις Άλπεις ορισμένα GCMs υπερεκτιμούν τα ύψη της θερινής βροχόπτωσης ενώ άλλα τα υποεκτιμούν. · Εν γένει οι διαφορές μεταξύ του «μέσου μοντέλου» από τις παρατηρήσεις είναι μικρότερες συγκριτικά με τις αντίστοιχες αποκλίσεις από τις παρατηρήσεις που παρουσιάζουν τα επιμέρους GCMs τόσο κατά το χειμώνα όσο και κατά το θέρος. Από την ανάλυση της συνολικής βροχόπτωσης στις δύο συνιστώσες της: την βροχόπτωση λόγω αστάθειας και την μεγάλης κλίμακας βροχόπτωση συμπεραίνουμε ότι: · Κατά το χειμώνα επί της συνολικής βροχόπτωσης το μέγιστο του ποσοστού της βροχόπτωσης λόγω αστάθειας παρατηρείται πάνω από τα θαλάσσια τμήματα της ευρύτερης περιοχής της Μεσογείου. Επίσης το συγκεκριμένο ποσοστό κατά το χειμώνα εν γένει αυξάνεται με την αύξηση της θερμοκρασίας αέρος επιφανείας. ......................................................................................................................................

Identifying Degraded and Sensitive to Desertification Agricultural Soils in Thessaly, Greece, under Simulated Future Climate Scenarios

The impact of simulated future climate change on land degradation was assessed in three representative study sites of Thessaly, Greece, one of the country’s most important agronomic zones. Two possible scenarios were used for estimation of future climatic conditions, which were based on greenhouse gas emissions (RCP4.5 and RCP8.5). Three time periods were selected: the reference past period 1981–2000 for comparison, and the future periods 2041–2060 and 2081–2100. Based on soil characteristics, past and future climate conditions, type of land uses, and land management prevailing in the study area, the Environmentally Sensitive to desertification Areas (ESAs) were assessed for each period using the MEDALUS-ESAI index. Soil losses derived by water and tillage erosion were also assessed for the future periods using existing empirical equations. Furthermore, primary soil salinization risk was assessed using an algorithm of individual indicators related to the natural environment or socio-economic characteristics. The obtained data by both climatic scenarios predicted increases in mean maximum and mean minimum air temperature. Concerning annual precipitation, reductions are generally expected for the three study sites. Desertification risk in the future is expected to increase in comparison to the reference period. Soil losses are estimated to be more important in sloping areas, due especially to tillage erosion in at least one study site. Primary salinization risk is expected to be higher in one study site and in soils under poorly drainage conditions

Identifying Degraded and Sensitive to Desertification Agricultural Soils in Thessaly, Greece, under Simulated Future Climate Scenarios

The impact of simulated future climate change on land degradation was assessed in three representative study sites of Thessaly, Greece, one of the country&rsquo;s most important agronomic zones. Two possible scenarios were used for estimation of future climatic conditions, which were based on greenhouse gas emissions (RCP4.5 and RCP8.5). Three time periods were selected: the reference past period 1981&ndash;2000 for comparison, and the future periods 2041&ndash;2060 and 2081&ndash;2100. Based on soil characteristics, past and future climate conditions, type of land uses, and land management prevailing in the study area, the Environmentally Sensitive to desertification Areas (ESAs) were assessed for each period using the MEDALUS-ESAI index. Soil losses derived by water and tillage erosion were also assessed for the future periods using existing empirical equations. Furthermore, primary soil salinization risk was assessed using an algorithm of individual indicators related to the natural environment or socio-economic characteristics. The obtained data by both climatic scenarios predicted increases in mean maximum and mean minimum air temperature. Concerning annual precipitation, reductions are generally expected for the three study sites. Desertification risk in the future is expected to increase in comparison to the reference period. Soil losses are estimated to be more important in sloping areas, due especially to tillage erosion in at least one study site. Primary salinization risk is expected to be higher in one study site and in soils under poorly drainage conditions

The ranking of the effect of proxies on the space and time variability of stratospheric ozone profiles

International audienceThe paper is focusing on the relative importance of proxy time series for explaining variations in the vertical ozone profiles. Studied proxies include (1) dynamical proxies (Quasi Biennial Oscillation (QBO), El Niño Southern Oscillation (ENSO), Arctic Oscillation (AO), Antarctic Oscillation (AAO) and Tropopause Pressure), extraterrestrial proxies (11-year solar cycle) and (3) stratospheric composition proxies (aerosol optical depth at 550 nm and equivalent effective stratospheric chlorine; EESC). Results are presented for ozone profiles from 5 well maintained Lidar stations located in the northern mid-latitudes, northern subtropics and southern mid-latitudes and collocated SBUV measurements. We present the short and long term ozone variability attributed to each proxy and its ranking at 7 vertical ozone layers over Hohenpeißenberg, Haute Provence, Table Mountain, Mauna Loa and Lauder