Spatial and Temporal Distribution of Rainfall and Temperature in Macedonia, Greece, Over a Thirty Year Period, Using Gis
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Bulletin of the Geological Society of Greece, vol. XLVII 2013 Δελτίο της Ελληνικής Γεωλογικής Εταιρίας, τομ. XLVII , 2013 Proceedings of the 13th International Congress, Chania, Sept. Πρακτικά 13ου Διεθνούς Συνεδρίου, Χανιά, Σεπτ. 2013 2013 SPATIAL AND TEMPORAL DISTRIBUTION OF RAINFALL AND TEMPERATURE IN MACEDONIA, GREECE, OVER A THIRTY YEAR PERIOD, USING GIS Grimpylakos G. 1, Karacostas T. S.2 and Albanakis K.1 1 Aristotle University of Thessaloniki, Faculty of Geology, Department of Physical and Environmental Geography, [email protected], [email protected] 2 Aristotle University of Thessaloniki, Faculty of Geology, Department of Meteorology and Climatology, [email protected] Abstract Due to increased demand and use of water resources, the European Union has es- tablished the (WFD) Water Framework Directive 2000/60 for Community action in the field of water policy. In order to achieve better water protection and manage- ment, Member States must identify and analyse European waters, on the basis of in- dividual river basin and district. Precipitation and air temperature are directly related and at the same way interact- ed to the hydrological cycle and therefore with water resources. The objective on this study is to present the spatial and temporal distribution of precipitation and air temperature in Macedonia, by using GIS software (ArcMap 9.3). The data used were retrieved from 82 different meteorological stations, which be- long to the Ministry of Rural Development and Food, and correspond to the thirty year period (1974-2004); all stations provided continuous daily data of precipitation while 43 of them provided also daily data of temperature. The annual temperature range and the annual total precipitation amount were calculated, at each individual station, for the thirty years of the examined period. By using GIS software and trian- gular interpolation scheme, the thematic maps of Macedonia for the aforementioned parameters and thermal continentality K were created. Furthermore, possible mean annual evapotranspiration for each meteorological station was estimated by Turc, Coutagne and Thornthwaite algorithms. Key words: Interpolation, Annual temperature range, Thermal continentality, Evap- otranspiration, Water Framework Directive. Περίληψη Η αυξημένη ζήτηση και χρήση των υδάτινων πόρων οδήγησε την Ευρωπαϊκή Ένωση στην καθιέρωση της Ευρωπαϊκής κοινοτικής Οδηγίας Πλαίσιο 2000/60 ΕΚ για τα ύ- δατα, η οποία έχει στόχο την καλύτερη πολιτική διαχείριση των υδάτων από τα κράτη μέλη. Προκειμένου να επιτευχθεί καλύτερη προστασία αλλά και διαχειρισή των υδάτι- νων πόρων, τα κράτη μέλη πρέπει να εντοπίσουνε και να αναλύσουνε τα ευρωπαϊκά ύδατα σε επίπεδο λεκάνης απορροής. Ο υετός και η θερμοκρασία του αέρα συνδέονται άμεσα και αλληλεπιδρούν με τον υ- δρολογικό κύκλο και με τους υδάτινους πόρους. Ο στόχος αυτής της μελέτης είναι να XLVII, No 3 - 1458 παρουσιάσει την χωρική και χρονική κατανομή του υετού και της θερμοκρασίας του αέρα στη Μακεδονία, με τη χρήση λογισμικού Γ.Σ.Π. (ArcMap 9,3). Τα δεδομένα που χρησιμοποιούνται είναι οι ημερήσιες, μηνιαίες και ετήσιες τιμές των παραπάνω παραμέτρων, οι οποίες ανακτήθηκαν από 82 διαφορετικούς μετεωρολογι- κούς σταθμούς που ανήκουν στο Υπουργείο Αγροτικής Ανάπτυξης και Τροφίμων, και αντιστοιχούν στο χρονικό διάστημα τριάντα χρόνων (1974-2004). Συγκεκριμένα 82 σταθμοί παρείχαν συνεχή δεδομένα ημερήσιου υετού ενώ 43 από τους σταθμούς πα- ρείχαν συνεχή δεδομένα της ημερήσιας θερμοκρασίας του αέρα. Το Ετήσιο Θερμο- κρασιακό Εύρος, η θερμική Ηπειρωτικότητα, η μέση ετήσια θερμοκρασία και το μέσο ετήσιο ύψος υετού υπολογίστηκαν, σε κάθε σταθμό, για τα τριάντα χρόνια της εξετα- ζόμενης περιόδου. Χρησιμοποιήθηκε το λογισμικό GIS (ArcMap 9.3) για την εφαρμο- γή μεθόδων χωρικής παρεμβολής, προκειμένου να προσδιοριστούν οι τιμές των παρα- πάνω παραμέτρων στη Μακεδονία. Ακολούθησε έλεγχος αξιοπιστίας των μεθόδων και η πιο αξιόπιστη μεθοδος χρησιμοποιήθηκε για την δημιουργία χαρτών με τις προανα- φερόμενες παραμέτρους. Έπειτα έγινε υπολογισμός της εξατμισοδιαπνοής για όλους τους μετεωρολογικούς σταθμούς με τρεις μεθόδους Thornthwaite, Turc και Coutange. Λέξεις κλειδιά: Ετήσιο θερμοκρασιακό εύρος, Βαθμός θερμικής ηπειρωτικότητας, Εξατμισοδιαπνοή, Κοινοτική Οδηγία 2000/60. 1. Introduction Precipitation, air temperature and evapotranspiration are directly related and interacted with the water cycle. This article is part of a research, which examines the spatial and temporal distribution of the aforementioned climatic parameters in Macedonia Greece, in order to decide if these parameters should be used as one of the alternative factors of System B for Greece’s river typology according to the (WFD) Water Framework Directive 2000/60 for Community action in the field of water policy. According to the WFD, Member States are obliged to classify all surface waters by one of the two typology systems, A or B. System A has fixed types with specific categorisation. System B can include alternative factors alongside with the obligatory factors of System A, but leaves to the analyst’s discretion the categorisation of these factors as long as the new typology achieves at least the same level of categorisation as System A. (Kanli, 2009). 2. Parameters, Data and Method 2.1. Climatic Parameters 2.1.1. Annual Temperature Range The annual course of temperature depends on the deviation of sun (position of sun according to earth in general), place’s latitude and the respective path of solar radiation. At North hemisphere, higher temperature is observed during July or August while minimum during January or February (Zampakas, 1981). Mean annual Temperature at each station, derives by calculating the mean monthly temperature for a 30-year period and abstracting from the maximum monthly temperature the minimum monthly temperature as shown at table 2. Annual temperature range can be used to categorise the climate type in 4 different types (Supan, 1880): i) A ≤ 15οC Equator climate type, ii) 15οC < Α ≤ 20οC Transitional maritime climate type and iii) 20οC < Α ≤ 40οC Continental climate type, iv) 40οC < Α Extreme continental climate type. 2.1.2. Parameter K of Thermal Continentality The index of thermal continentality, parameter K, which is most often used in Europe was proposed by Gorczynski in 1918, (Mikolaskova, 2009). XLVII, No 3 - 1459 Equation 1 – Gorczynski for Thermal Continentality K = 1,7(Α - 12sinθ)/sinθ or K = 1,7Α/sinθ – 20.4 Parameter K is the index of continentality expressed as a percent, A is annual range of temperature in °C and θ is latitude in degrees (WGS84). Expression A=12sinθ corresponds well to observations above sea (Gorczynski, 1922), constant 1.7 is calculated from the assumption that Verchojansk, in eastern Siberia, is representative of 100% continentality. K value range is 0-100, where 0 is observed at sea locations, where climate is no longer influenced by continental surface and 100 at purely continental areas, where there is no influence from maritime air masses. This parameter is not applicable at low latitudes (Conrad and Pollak, 1950) but it is applicable in Greece. Gorczynski suggests three degrees of continentality according to parameter K value: i) 0% ≤ K ≤ 33% Transitional maritime climate type, ii) 33% < K ≤ 66% Continental climate type and iii) 66% < K ≤ 100% Extreme continental climate type. 2.1.3. Evapotranspiration Although several variations of the definition exist, potential evapotranspiration (PET) can be generally defined as the amount of water that could evaporate and transpire from a vegetated landscape without restrictions other than the atmospheric demand (Thornthwaite, 1948; Penman, 1948; Jensen et al., 1990). Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. To estimate ET, three methods were used in this study: Turc, Coutagne and Thornthwaite. These methods need the mean monthly and annual precipitation and the mean monthly and annual temperature. Turc algorithm, equation 2, for estimating ET, uses P mean annual precipitation in mm and T which is the mean annual temperature in °C. Equation 2 – Turc algorithm for Evapotranspiration E= P/√(0,9+P2/L2) , with L=300+25T+0,05T3 Coutagne algorithm, equation 3, for estimating ET is applicable when the condition 1/8λ≤ P ≤ 1/λ is valid, P is the mean annual precipitation in meters and T is mean annual temperature in °C. Equation 3 – Coutagne algorithm for Evapotranspiration E= P-λ P2, with λ=1/(0,8+0,14T) Thornthwaite algorithm requires latitude, daylight coefficient, soil moisture, mean monthly precipitation in mm and mean monthly temperature in °C (Palmer & Havens, 1958; Pereira & Camargo, 1989; Kerkikdes et.al., 1996; Mardikis et al., 2005; Dalezios & Bartzokas, 2009). Equation 4 – Thornthwaite algorithm for Evapotranspiration c 12 1,514 PETi(L)=K*PETi(0) , PETi(0)=1,6*(10Ti/J) , J=Σi=1 (Ii) and Ii=(Ti/5) 3 2 Ti=mean i monthly temperature and C=0,000000675*J – 0,0000771*J + 0,01792*J +0,49239 PETi(0) = Potential Evapotranspiration at 0 latitude. Constant K differs according to latitude. For our case study at all meteorological stations the same constant K values were used and these are shown at table 1. Table 1 – Constant K values in Thornthwaite Method. Month Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec K 0,83 0,83 1,3 1,11 1,25 1,26 1,27 1,19 1,04 0,96 0,82 0,8 XLVII, No 3 - 1460 Average monthly precipitation is estimated by averaging the overall precipitation for each month for 1974-2004. Mean annual precipitation is very reliable measured at points where meteorological stations are situated and was estimated by summing the average monthly precipitation for the same period. Average monthly temperature is estimated by averaging the average temperature for each month during the period of 1974-2004. Mean annual temperature was estimated by averaging the monthly average temperature for the aforementioned period. 2.2. Studying Area and Data Macedonia is a district of North Greece as shown at figure 1. Studying area is a polygon that includes all the watersheds of Macedonia’s torrents and rivers, resulting in a polygon the boundaries of which differ from the boundaries of Macedonia’s political district.