Trends of different agroclimatic parameters in Spain Antonio Mestre State Meteorological Agency of Spain
Overview In the last twenty years there have been changes in the agricultural activities timing in several crops. Although many of those changes can be explained by changes in species or in harvesting methods, there have also been changes in some of the recorded phenological phases (for instance, in almond tree flowering or the arrival of some migratory birds). Although there are numerous studies on the impact of climate change on crop yields or food production, most of them use model projections for fifty or more years of annual averaged temperatures and rainfall, and in many cases it remains still unanswered the question on the convenience of changes in crops or harvesting methods for changes in the near future (next ten years) or for those which have already taken place. In this last case, the first question to deal is to establish whether have been changes and to determine them as accurate as possible. The aim of this study was mainly to answer if there have been changes in some agroclimatic parameters, such as mean maximum and minimum temperatures, precipitation, frost days, number of days with maximum temperature exceeding predefined thresholds, sunshine, wind run, evapotranspiration, SPI. Mainly focused in the vegetative period (February to June, both included).
Study data For the trend analysis the daily data of temperature, precipitation, sun hours, wind, for a set of representative meteorological stations in each study zone corresponding to a Spanish climatic zone were used. The gaps in data series were filled. The period used in the study was in general from 1960 to 2010: period from February to June (temperature, precipitation, sun hours, wind ). Climatic zones 1. Galicia and Norther coastal zone (meteorological stations: Vigo Peinador, Santiago Labacolla, Oviedo aeropuerto, Bilbao Sondica, San Sebastián Igueldo, Vitoria Foronda). 2. Northern Plateau (meteorological stations: León Virgen del Camino, Burgos Villafría, Salamanca Matacán, Valladolid Villanubla). 3. Southern Plateau (meteorological stations: Madrid Barajas, Molina de Aragón, Cuenca, Albacete Los Llanos) 4. Guadiana and Guadalquivir river basins (meteorological stations: Talavera la Real (Badajoz), Córdoba aeropuerto, Granada Armilla, Sevilla San Pablo, Morón, Jerez aeropuerto, Cádiz). 5. Ebro's river basin (meteorological stations: Daroca, Logroño Agoncillo, Zaragoza aeropuerto, Huesca Monflorite, Pamplona, Teruel) 6. Mediterranean coastal zone (meteorological stations: Barcelona aeropuerto, Reus, Tortosa, Valencia, Valencia Manises, Alicante El Altet, San Javier (Murcia), Alcantarilla (Murcia), Almería aeropuerto, Málaga aeropuerto).
Results of the trend study Temperature. Results for mean value of T min and T máx along the vegetative season. Results for frost days and number of hot days. Results for last frost day Precipitation. Total precipitation Number of days with precipitation exceeding predefined tresholds Extreme precipitations: Heavy rainfall in different time intervals SPI. Results for drought index (mean areal SPI series). Sun hours. Water Balance Elements. Climate Water Balance
Trends of daily maximum temperature: 1960-2010 (Vegetative period average)
Trends of daily maximum temperature: 1985-2010 (Vegetative period average)
Trends of daily minimum temperature: 1960-2010 (Vegetative period average)
Trends of daily minimum temperature: 1985-2010 (Vegetative period average)
T (ºC) Tmax (average value in vegetative Season) Tmax in Talavera la Real: Average value in vegetative season (Feb-June). 30,0 25,0 20,0 15,0 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
N Number of days with Tmax > 30ºC in Vegetative Season number of days with Tmax>30ºC in vegetative season in Talavera la Real 45 40 35 30 25 20 15 10 5 0 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
T Cº) Tmin (average value in vegetative Season) Tmín in Talavera La Real: Average value in Vegetative Season (Feb-June) 12,0 11,0 10,0 9,0 8,0 7,0 6,0 5,0 4,0 1940 1950 1960 1970 1980 1990 2000 2010 2020 Year
N Number of frost days in vegetative Season Number of frost days in Talavera la Real in vegetative season 30 25 20 15 10 5 0 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
T (Cº) Number of frost days 20 Number of frost days in the vegetative season in Santiago de Compostela 18 16 14 12 10 8 6 4 2 0 1950 1960 1970 1980 1990 2000 2010 year 13
julian day Some results for last frost day Series of Last frost days in Don Benito (Badajoz): 1970-2006 120 y = -0,6792x + 1411,2 R 2 = 0,0864 100 80 60 40 20 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 year
Summary of Results for last frost day Agricultural Zone Trend slope (days/ decade) : 1970-2007 Significance level Don Benito (Extremadura) -6,80 No sig Lorca (Murcia) -10,33 *** (p<0,005) Liria- Huerta de Valencia ( Valencia) -5,65 No sig. La Almunia -Zaragoza (Aragón) -5,65 *(p<0,05) Manises (Valencia) -10,35 *(p<0,05) Segria- Lleida (Catalonia) -6,82 *(p<0,05) Ribera de Navarra -0,75 No sig Urgell- Lleida ( Catalonia) -4,05 No sig Mean value for all zones -6,30
julian day Trends in fruit-tree phenology Trends in phenology in Spain (flowering of fruit-trees in Cardedeu station) 140 120 100 malus domestica y = -1,0506x + 2186,2 R 2 = 0,6322 80 pirus communis y = -0,451x + 974,76 R 2 = 0,2063 60 y = -0,3755x + 802,94 R 2 = 0,1323 40 y = -0,3287x + 687,49 R 2 = 0,056 Prunus dulcis prunus domestica 20 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 year
Trends of total precipitation in vegetative periode: 1960-2010
Precipitation trends over Spain
P (mm) Trends in average precipitation over Spain in vegetative Season Mean precipitation over Spain in the Vegetative Season (February -June) 450 400 350 300 250 200 150 100 50 0 1950 1960 1970 1980 1990 2000 2010 2020 Year
Precipitation trends over Spain Mean monthly precipitation over the Spanish territory mm 90 80 70 60 50 40 30 20 10 0 January February March April Mai June July August September October November December 1981-2007 1950-1980 month
P(mm) Precipitation trends over Spain Total precipitation (mm) in the vegetative season in Talavera la Real (Badajoz) 400 350 300 250 200 150 100 50 0 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
N Trends of the number of rainy days. Number of days with precipitation greater than 0,1 mm in Talavera la Real (Badajoz) 60 50 40 30 20 10 0 1940 1950 1960 1970 1980 1990 2000 2010 2020 Year
precipitación (mm) Trends in heavy rainfall events Serie of maximum anual precipitation in a day in San Sebastián-Igueldo 180.00 160.00 140.00 120.00 100.00 80.00 60.00 y = -0.0044x + 82.408 R 2 = 1E-05 40.00 20.00 0.00 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 año
precipitation (mm) Trends in heavy rainfall events serie of annual maximum precipitation in a day in Barcelona (El Prat) 200,00 180,00 160,00 140,00 120,00 100,00 80,00 60,00 y = 0,0014x + 68,013 R 2 = 6E-07 40,00 20,00 0,00 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
Precipitation (mm) Trends in heavy rainfall events Serie of annual maximum precipitation in a day in Madrid (Retiro) 100,00 90,00 80,00 70,00 60,00 50,00 40,00 30,00 20,00 y = -0,0423x + 116,23 R 2 = 0,0095 10,00 0,00 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
mm Trends in heavy rainfall events Annual maximum values of hourly precipitation in San Sebastian (Pais vasque-north Spain) 120 100 80 60 40 20 y = 0.1204x - 210.13 R 2 = 0.0439 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 año
mm/hora Trends in heavy rainfall events serie of annual maximum rainfall intensity in 10 minutes and annual number of rainfall events with I10 > 25 mm/hour (blue line) in S. Sebastian-Igueldo. 180 50 160 45 140 40 120 100 80 60 y = 0.3678x + 54.057 R 2 = 0.1053 35 30 25 20 15 40 10 20 5 0 0 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 año
mm/hour Trends in heavy rainfall events Series of Annual Maximum Intensity of Precipitation in 1 hour (red line) and 10 minutes (blue line) in Santander (North Spain) 180 160 140 120 100 80 60 y = 0.5792x + 33.411 R 2 = 0.1452 I60 I10 Lineal (I10) Lineal (I60) 40 20 0 1942 1945 1948 1951 1954 1957 1960 1963 1966 1969 1972 1975 1978 year 1981 1984 1987 1990 1993 1996 1999 y = 0.0413x + 18.165 R 2 = 0.0122 2002 2005
Summary results for trends in heavy rainfall (24 hours) Station Trend slope (% variation/ decade) : 1950-2007 Significance level La Coruña (Galicia) +1,63 Nosig San Sebastián (Vasque Country) -0,06 Nosig Logroño (la Rioja) +0.120 Nosig Barcelona (Catalonia) +0,20 Nosig Salamanca (Castille-Leon) -2,16 Nosig Cáceres (Extremadura) +7,37 Valencia -1,35 Nosig Madrid -0,012 Nosig Mçalaga (Andalucia) +1,88 Nosig
Summary results for trends in heavy rainfall (1 hour) Station Trend slope (% variation/ decade) : 1950-2007 Significance level La Coruña (Galicia) +0,64 Nosig San Sebastián (Vasque Country) +4,48 Nosig Logroño (la Rioja) +5,60 *(p<0,05) Barcelona (Catalonia) +2,35 **(p<0,01) Salamanca (Castille-Leon) +2,02 Nosig Cáceres (Extremadura) +1,63 Nosig Valencia +0,27 Nosig Madrid +3,04 Nosig Santander +2,09 Nosig
Summary results for trends in heavy rainfall (10 minutes) Station Trend slope (% variation/ decade) : 1950-2007 Significance level La Coruña (Galicia) -0,66 No sig San Sebastián (Vasque Country) +5,25 *(p<0,05) Logroño (la Rioja) +5,08 *(p<0,05) Barcelona (Catalonia) +2,12 **(p<0,01) Salamanca (Castille-Leon) +4,16 No sig Cáceres (Extremadura) +8,04 *(p<0,05) Valencia +1,08 No sig Madrid +4,05 No sig Santander +10,97 *** (p<0,005)
SPI Trends of SPI series Serie of SPI-12 values for Peninsular Spain (mean monthly precipitation) 4 3 y = -0.0004x + 0.1506 R 2 = 0.0077 2 1 0 1947 1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007-1 -2-3 -4 año
Trends of SPI series Serie of SPI 1 (31 Marzo) para el conjuunto de España 3 2 y = -0.0171x + 33.912 R 2 = 0.0937 1 0 1940 1950 1960 1970 1980 1990 2000 2010 2020-1 -2-3 -4
SPI value Trends of SPI series SPI-12 months (blue line) and SPI 6 (red line) in Mai 3 2,5 2 y = -0,0075x + 14,873 R 2 = 0,0175 1,5 1 y = -0,0102x + 20,235 R 2 = 0,0313 0,5 0-0,5 1940 1950 1960 1970 1980 1990 2000 2010-1 -1,5-2 -2,5 year
Insolation (hours) Trends in Total Insolation in the Vegetative Season Total Insolation in Zaragoza in Vegetative Season (February- June) 1600 1400 1200 1000 800 600 400 1950 1960 1970 1980 1990 2000 2010 2020 Year
N (Hours) Trends in Total Insolation in the Vegetative Season Total Insolation in Vegetative Season in Talavera La Real 1600 1400 1200 1000 800 600 400 1940 1950 1960 1970 1980 1990 2000 2010 2020 year
P-E (mm) Trends in Climatic Water Balance in Vegetative Season P-ET (Climatic Water Balance) in Zaragoza (february-june) 100 50 0 1961 1966 1971 1976 1981 1986 1991 1996 2001 2006-50 -100-150 -200-250 -300-350 year
P-ET (mm) Trends in Climatic Water Balance in Vegetative Season Climate Water Balance (P-ET) in vegetative season in Murcia (Alcantarilla) 150 100 50 0-50 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009-100 -150-200 -250-300 year
Main Conclusions In the last sixty years there has been an increase of maximum and minimum temperature averages, as much in the annual averages as in the vegetative period averages. Nevertheless, such temperature increases have not been even throughout the whole period, and it amounted from 1º C to 2º C in all zones. There have also been increases in the number of hot days (maximum temperature over 30º C) and decreases in the number of frost days (minimum temperature under 0º C) in most of the stations. The period of risk of frosts have shortened, and the last frost day occurs earlier, nevertheless flowering occurs earlier too and the number of severe cold spells and their intensity remains the same. The risks of damaging frosts affecting main fruit-trees areas in Spain remains due to the fact that cold spells well into the springtime are still occurring.
Main conclusions About the amount of precipitation, it can be said that there has been a decrease in the amount of precipitation registered in annual periods as well as in vegetative periods in all the Atlantic basins, while it has remained more or less constant in the Mediterranean basins. The decrease of the amount of precipitation has been small in the northern half of the Atlantic basins and more accused in the southern basins. About the number of days with precipitation and the number of days with thunder storms, there are no trends in Galicia and Northern coastal zone, Northern and Southern Plateaus and the Guadiana and Guadalquivir river basins, but there has been a slight increase in the intensity of short duration showers. It is to remark that there has been an accused decrease in the amount of precipitation (around 50%) registered in the months of February and March in the Northern Plateau and Southern Plateaus and in the Guadiana and Guadalquivir river basins. There are increases in the number of days of precipitation, number of days of thunder storms in the Ebro river basin and Mediterranean coastal zone. In the Mediterranean coastal zone there is a decrease in the interannual variability (which is, in general, quite marked). In these zones, there is a slight negative trend for the months of February and March. About precipitation intensity (extreme events), the annual series of daily maximum precipitation in a set of Spanish stations do not show significant trends, but in shorter time scales it appears, in some cases, significant trends, particularly in the stations located in north Spain.
Main conclusions. In the first 30 years (1950-1980) of the considered period there is a negative trend in the amount of sun hours, and a positive trend afterwards (1980-2009), to recover in the last decade the annual sun hours of the 50's in Galicia and Northern coastal zone, the Northern and Southern Plateaus, the Guadiana, Guadalquivir and Ebro river basins. In Mediterranean coastal zone there is a slight variation of the pattern. Three periods can be distinguished in this zone. The first, from 1950 to 1985, with a decrease in the number of annual sun hours; a second, from 1985 to 2000, with a marked increase; and a third, the last ten years, in which there is a decrease. Around 2000 the number of annual sun hours recovered the values of the 50's (around 3000), but at present the number is similar to that of the 70's (around 2800). The series of Climate Water Balance P- ET show some trends to decreasing values, particularly in central and southern Spain. It is difficult to reach a conclusion in the case of wind parameters with long series (wind run and gusts' maximum speed). Their interannual variability is quite high in both parameters. In many stations there seems to be an increase in wind run and a decrease in gusts' maximum speed, but changes have been so marked as to suggest that it was due to changes in the kind of measurement instruments or changes in the placement of the anemometer.
Main conclusions Finally, it is to remark that spanning the period to the beginning of the XX Century (there are several series of temperature and precipitation in which that can be done, four of them quite reliable), one finds that for temperature trends are positive for the long period as a whole in spite of shorter periods with negative or no trends, while the amount of annual precipitation was bigger in the 60's and 70's and more or less the same in the rest of the period.
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