agroclimatic parameters in Spain Spain Antonio Mestre State Meteorological Agency WMO/COST 734 Symposium: Aas (Norway) 4-64

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1 Trend analysis of long series of agroclimatic parameters in Spain Antonio Mestre State Meteorological Agency Spain

2 Outline Objetive of the agroclimatic trend project Study zones Data Some results of trend analysis: 1. Minimum temperatures 2. Last frost days 3. Preliminary Conclussions Extension to other agroclimatic parameters.

3 Overview of the agroclimatic study The initial phase of this project has been carried out in the framework of a collaboration with the agrarian insurance sector in response to a demand from Agroseguros (Insurance Company in the Spanish agrarian sector). The main goal of the study is the detailed analysis of frost risks in agricultural areas and its future trends aimed at helping to establish adequate insurance policies. Taking into account that the interest of the contracting firm was frost risks s for fruit trees, we focussed the study in cold spells (irruption of air very cold and dry, which can cause black frost (not visible. there are no ice crystals due to lack of humidity). The study outputs include for each of the selected agricultural areas: a) total number of periods with frost for each season, specially in springtime b) mean length of those periods c) frosts intensity d) size of the affected area by the frost. e) persistence. Probability of periods of successive frost days. f) Synoptic situation which gives rise to frost conditions. g) Trend analysis

4 Overview of the agroclimatic study In the Iberian Peninsula and Balearic Islands the more severe frost situation occur when cold air from the northeast flows into the region caused by a high pressure system in the Atlantic extending to the British Isles and Scandinavia together with low pressure in the Mediterranean sea. When combined with continentality and altitude, cold spells plus irradiation can cause very low temperatures in the interior of the Peninsula: -3º C, January, 2, 1971 in Molina de Aragón, -24º C, January, 3, 1971 in Albacete, -2,4º C, January, 17, 1945 in Avila. Even in the coasts minimum temperatures could reach -3º C in some occasions. Risk is bigger in zones in which the frequency of frost days is lower (these are the zones appropriate for cultivars of some fruit trees: citrus fruits, etc). Frosts in February affect flowering of almond tree, apricot tree, medlar tree, citrus trees, etc. Frosts in March or April affect prune tree, cherish tree, apple tree, pear tree, etc. As a complementary study we wondered whether climate change would d affect the insurance company policies in the near future (ten years or so) and to this s effect carried out an analysis of trends. Is there any trend in minimum temperatures in the sensible season n for fruit trees? Are there changes in the dates of the last frost day in springtime? Being March the crucial month for the cultivars of interest (flowering occurs mainly in this month in the areas of our study) the study of trends in minimum temperatures res was carried out for this month. In most testing areas, the study of trends was also extended to February. A common period of 36 agricultural years ( to 25-6) 6) was used.

5 Study zones

6 Study zones

7 Study Data Daily minimum temperatures data for the period from a set of representative meteorological stations (synoptical( and secondary stations, with professionals and volunteers) in each zone under study were used in the study. The gaps in data series were filled. A study aimed to analysing the synoptic situation in relation with the minimum temperatures and to obtain a classification and frequency y of cold spells has been also undertaken (1961 to 26).

8 Some results for minimum temperatures Serie of mean minimum temperatures anomalies in Alcantarilla (Murcia region) in february ( ) 3 y =,149x - 29,411 R 2 =, Mean anomaly (ºC)

9 Some results for minimum temperatures Serie of Minimum temperature anomalies in Alcantarilla (Murcia Region) in March: y =,562x - 111,73 R 2 =, mean anomaly (ºC)

10 Some results for minimum temperatures Serie of mean minimum temperatures anomalies in Talavera la real (Extremadura) in February: y = -,179x + 35,628 R 2 =, Mean anomalies (ºC)

11 Some results for minimum temperatures Serie of Mean Minimum temperatures anomalies in Talavera la Real (Extremadura region) in March: y =,591x - 117,74 R 2 =, Mean anomaly (ºC)

12 Some results for minimum temperatures Serie of mean minimum temperature anomalies in Zaragoza (Aragón) in february: y = -,35x + 7,4247 R 2 =,7 2 mean anomaly (ºC)

13 Some results for minimum temperatures Serie of mean minimumu temperarure anomalies in Zaragoza (Aragon) in March): y =,638x - 126,64 R 2 =,

14 Summary results for T trends mín Agricultural Zone Trend slope (ºC/ decade) ) in February (197-27) Significance level Trend slope (ºC/ decade) ) in March (197-27) Significance level Alcantarilla (Murcia),15 No sig,56 *** (p<,5) Sevilla (Andalucía),35 No sig 1,21 *** (p<,5) Talavera (Extremadura) -,5 No sig,59 *** (p<,5) Zaragoza (Aragón) -,3 No sig,64 *** (p<,5) La Plana (Valencia),44 ** (p<,1) 1,17 *** (p<,5) Huerta de Valencia ( Valencia),22 No sig 1,1 *** (p<,5) Ribera de Júcar (Valencia),11 No sig,79 *** (p<,5) Alicante South (Valencia),6 No sig,79 *** (p<,5) Mean value for all zones,14,8

15 Some results for last frost day Series of Last frost days in Don Benito (Badajoz): y = -,6792x ,2 R 2 =, julian day year

16 Some results for last frost day Series of last frost days in Lorca (Murcia): y = -1,327x + 211,6 R 2 =, julian day year

17 Some results for last frost day Serie of last frost day in La Almunia ( Zaragoza): y = -,5649x + 123,8 R 2 =, julian day year

18 Some results for last frost day Serie of last frost days in Liria (Valencia): y = -,5664x ,9 R 2 =,578 julian day year

19 Some results for last frost day Series of last frost days in Rivera de Navarra: (197-25) 12 y = -,754x + 226,17 R 2 =,2 1 8 julian day year

20 Some results for last frost day Serie of last frost days in Segria (Lleida): y = -,6824x ,7 R 2 =, julian day year

21 Summary results for last frost day trends Agricultural Zone Trend slope (days/ decade) ) : Significance level Don Benito (Extremadura) -6,8 No sig Lorca (Murcia) -1,33 *** (p<,5) Liria- Huerta de Valencia ( Valencia) La Almunia -Zaragoza (Aragón) -5,65-5,65 No sig. *(p<,5) Manises (Valencia) -1,35 *(p<,5) Segria- Lleida (Catalonia) -6,82 *(p<,5) Ribera de Navarra -,75 No sig Urgell- Lleida ( Catalonia) -4,5 No sig Mean value for all zones -6,3

22 Precipitation trends over Spain Mean monthly precipitation over the Spanish territory mm January February March April Mai June July August September October November December month

23 Precipitation trends over Spain Time serie of mean precipitation in february-march over Spain mm y = x R 2 = year

24 Trends in fruit-tree tree phenology Trends in phenology in Spain (flowering of fruit-trees in Cardedeu station) malus domestica y = -1,56x ,2 R 2 =,6322 julian day 8 6 pirus communis y = -,451x + 974,76 R 2 =,263 y = -,3755x + 82,94 R 2 =, y = -,3287x + 687,49 R 2 =,56 Prunus dulcis prunus domestica year

25 Preliminary conclusions. There is a clear positive trend in minimum temperatures in March and a negative trend in the last frost day (the last frost day occurs earlier), but no recent trend is detected in minimum temperatures in February. As apart from this, a significative reduction in precipitation in both February and March since the 7 s has been observed So, It is true that 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. To this respect, it is quite remarkable the occurrence of frost days in March in the agricultural years of and in several areas (in Levante and Andalucía) which were free or almost free of frost in springtime (period from the first of March to May) in the previous ten or fifteen years. The risks of damaging frosts affecting main fruit-trees trees areas in Spain remains due to the fact that cold spells well into the springtime e are still occurring.

26 Future activities The project of detection and analyisis of trends in agoclimatic indices is now been extended to other parameters in the framework of the COST 734-WG2 activities: Trend analysis of Drought Indexes (SPI) over the mediterranean area: this study will be carried out in collaboration with the italian team (V. di Stefano). Trend analysis of water balance elements. Trend analysis of forest fire risk indexes.

27 Some results for other agroclimatic variables: trends in SPI Spain mean precipitation: SPI-12 months and SPI 6 in Mai 3 2,5 2 y = -,75x + 14,873 R 2 =,175 1,5 1 y = -,12x + 2,235 R 2 =,313 SPI value, ,5-1 -1,5-2 -2,5 year

28 Some results for other agroclimatic variables Serie of SPI 1 (31 March) for Spain (mean areal precipitation) 3 2 y = -,171x + 33,912 R 2 =,

29 Some results for other agroclimatic variables 3 Time serie of Fire Weather Index value in Alicante during fire seasons y =.9x R 2 = FWI time

30 Some results for other agroclimatic variables 45 Time serie of Fire Weather Index value in Ciudad Real during fire seasons: y =.24x R 2 = FWI time

31 Thanks

Agricultural productivity and water supply variability in Spain: a model to manage hydrological risks

International Drought Symposium Integrating Science and Policy March 24th March 26th, 2010, California USA Agricultural productivity and water supply variability in Spain: a model to manage hydrological