Weather and Climate Is Available As a Download
Total Page:16
File Type:pdf, Size:1020Kb
Chapter 2 Weather and Climate Ken Cook and Ian Findlay Weardale weather © Ian Turner Introduction The Pennines are unique in England as the only significant upland area not close to the sea, with climatic implications. The high hills (up to 740 m AOD at the source of the Wear) maintain wet and cool conditions in the upper Dale and cast a rain shadow, creating drier conditions to the east. Yet gales from the north and east can bring heavy rain, and snow in the winter. Neighbouring Teesdale is unique in having more data and long-term weather stations than any other UK upland area. A continuous temperature record is available from 1931 (Holden & Adamson, 2001). Gordon Manley of Durham University began recording at Moor House at 550 m in the 1950s. Some parallels may be drawn from these records for Weardale, where local records go back to 1970. 41 What are conditions like? Gordon Manley summarised the climate at high altitudes in the Pennines as follows; ‘We therefore form a conception of excessively windy and pervasively wet autumn, a very variable and stormy winter with long spells of snow cover, high humidity and extremely bitter wind, alternating with brief periods of rain and thaw. April has a mean temperature little above the freezing point and sunny days in May are offset by cold polar air, while the short and cloudy summer is not quite warm enough for the growth of trees. Throughout the year, indeed, the summers are frequently covered in cloud’. The climate above 750 m is tundra/sub-polar oceanic. Cool, wet conditions have dictated a range of vegetation and associated fauna in the upper Dale. Blanket bog, rare in a global context, is common above 500 m on limestone and other rock types. Climatic conditions allow some plant growth but only partial decomposition of dead material, forming peat to a depth of around 2 m. At altitudes above 350 m, the growing season is very short, even with ‘the best weather’, with implications for wildlife and hill farmers. And extreme climatic events are a characteristic of uplands weather, including severe winters with late-winter and heavy snowfall or prolonged snow cover. Weather has dictated the rate of farming practice, particularly up to 1960 when the horse Temperature range, was relied upon rather than the tractor. Bollihope © Ian Turner Records 1981 to 2010 The following data show 30-year means from three weather recording stations moving down the Dale from west to east and the graph shows how snowy it has been in Copley. Below 7˚C vegetation does not grow, the invertebrate prey of nesting birds may be hard to find – inactive, trapped in frozen mud or buried in snow. Temperature means and Precipitation (pptn), 19812010 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Westgate max (˚C) 4.7 5.1 7.3 10.3 13.6 16.1 18.3 17.7 15.3 11.5 7.8 5.2 11.1 335 AOD min (˚C) –0.2 –0.3 1.1 2.5 4.9 7.9 10.1 9.8 7.8 5.4 2.5 0.2 4.3 pptn (mm) 110 85 87 74 62 65 62 71 83 105 120 115 1,038 Stanhope max (˚C) 6.1 6.9 9.6 13.1 16.6 19.2 21.3 20.6 17.9 13.6 9.3 6.5 13.4 215 AOD min (˚C) 1.1 1.2 2.8 4.3 6.9 9.9 12.1 11.6 9.5 6.8 3.8 1.5 6.0 daily 3.6 4.1 6.2 8.7 11.8 14.5 16.7 16.9 13.7 10.2 6.5 4.0 9.7 pptn (mm) 77 62 58 66 50 60 62 61 81 94 99 98 866 Copley max (˚C) 5.0 5.3 7.6 10.7 14.2 17.0 19.2 18.4 15.7 11.6 7.9 5.9 11.5 253 AOD min (˚C) –0.1 –0.1 1.3 2.6 5.1 7.9 10.3 10.1 8.4 5.6 2.5 0.5 4.5 daily 2.4 2.6 4.4 6.7 9.6 12.4 14.7 14.2 11.9 8.6 5.2 2.9 8.0 pptn (mm) 75 70 66 64 52 64 71 70 65 95 84 88 864 The average number of snow falling days throughout the year. Based on 1981-2010 averages, source Met Office. Data for table and chart provided by Ken Cook, source Met Office. 43 Weather data at Copley, 20012010 Temperature ˚C Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Mean daily max. 5.4 5.9 8.8 11.5 14.5 17.6 19.5 18.8 16.3 12.1 8.3 5.1 12.0 Mean daily min. 0.3 –0.1 0.9 2.9 5.3 8.3 10.3 10.5 8.6 5.8 2.7 –0.1 4.6 Mean temperature 2.9 2.9 4.5 7.2 9.9 12.9 14.9 14.7 12.5 8.9 5.6 2.5 8.3 Highest maximum 12.5 13.9 15.9 22.6 27.7 26.6 30.0 28.4 24.7 20.0 16.2 14.4 30.0 Year 2003 2008 2009 2007 2010 2005 2006 2003 2006 2007 2007 2003 17/7/06 Lowest minimum –9.7 –10.7 –12.8 –4.9 –4.2 0.6 3.6 3.3 1.2 –2.4 –9.4 –10.4 –12.8 Year 2002 2008 2001 2003 2010 2005 2002 2005 2007 2008 2010 2010 3/3/01 Lowest grass min. –17.2 –15.9 –18.5 –10.1 –10.0 –4.1 –3.3 –0.9 –2.9 –8.9 –16.3 –18.6 –18.6 Year 2002 2008 2001 2002 2010 2005 2006 2005 2003 2008 2010 2005 29/12/05 Highest minimum 8.4 8.0 8.5 11.3 12.1 15.6 15.8 17.5 14.5 12.1 12.0 8.1 17.5 Year 2004 2004 2006 2007 2003 2005 2006 2004 2003 2005 2007 2005 9/8/04 Lowest maximum –1.6 –0.7 –0.7 3.9 6.0 6.4 11.1 12.5 8.5 3.8 –2.5 –2.9 –2.9 Year 2010 2003 2006 2008 2010 2009 2004 2007 2007 2008 2010 2010 17/12/10 Air frosts 15.9 15.8 12.2 6.0 1.3 0.0 0.0 0.0 0.0 1.6 6.6 16.0 75.4 Concrete slab frosts 19.2 17.9 13.8 6.9 1.2 0.0 0.0 0.0 0.1 2.9 10.3 18.6 90.9 Earth temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 30cm depth (am) 4.0 3.9 4.9 8.0 11.3 14.3 16.0 16.2 14.3 11.0 7.7 4.9 9.7 100cm depth (am) 5.3 4.9 5.2 7.3 9.9 12.6 14.3 15.0 14.0 11.7 9.1 6.5 9.7 Precipitation mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Monthly mean 73.4 70.5 57.3 52.0 46.5 73.2 94.4 80.0 65.5 89.5 80.2 80.3 862.8 rain days =>0.2mm 21.5 15.3 15.9 14.5 15.2 13.7 17.0 16.4 13.9 19.1 19.4 18.5 200.4 wet days =>1.0mm 14.1 11.4 10.6 9.7 10.2 9.8 11.0 11.0 8.9 13.9 13.1 13.1 136.3 Days =>5.0mm 4.3 4.9 3.4 3.8 2.6 4.5 4.9 4.1 4.0 6.3 5.0 6.1 53.9 Wettest day 30.1 31.0 27.7 25.4 29.2 30.2 87.9 53.1 56.5 30.7 28.4 33.2 87.9 Year 2005 2009 2005 2009 2006 2007 2009 2004 2008 2002 2009 2002 01/07/09 Wettest month 133.9 151.3 113.2 106.4 120.7 187.6 267.9 250.4 119.3 154.2 184.7 142.9 1,008.1 Year 2008 2002 2006 2001 2006 2007 2009 2004 2008 2002 2009 2002 Driest month 14.0 28.0 26.6 13.4 18.4 21.1 19.7 10.3 20.1 23.6 14.6 42.1 590.7 Year 2006 2008 2009 2007 2004 2006 2006 2003 2009 2007 2004 2010 44 Sunshine hours Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Monthly mean 71.4 94.5 135.6 151.1 183.0 158.4 162.1 145.7 130.6 100.1 82.8 72.3 1,487.6 Daily mean 2.30 3.37 4.37 5.04 5.90 5.28 5.23 4.70 4.35 3.23 2.76 2.33 4.07 Days nil sunshine 7.7 4.9 4.3 2.4 2.1 2.6 2.0 1.5 2.8 6.0 5.4 9.1 50.8 Sunniest day 8.1 9.8 12.5 13.8 16.4 16.2 16.1 13.9 12.7 10.7 8.5 7.0 16.4 Year 2006 2004 2009 2009 2009 2010 2006 2003 2002 2007 2006 2001 30/5/09 Sunniest month 101.3 132.2 200.2 204.2 254.5 211.6 305.6 185.1 163.4 136.1 127.4 89.4 1,707.0 Year 2007 2008 2003 2007 2001 2010 2006 2007 2005 2003 2005 2006 Dullest month 61.8 66.7 75.4 92.9 125.9 103.5 126.5 87.4 83.9 40.0 55.0 35.4 1,272.2 Year 2002 2010 2005 2004 2002 2007 2010 2008 2008 2005 2002 2002 Wind KT Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Monthly mean, 10m 12.5 11.0 10.6 9.0 8.7 7.7 7.6 7.8 8.6 9.0 10.9 10.8 9.5 Highest gust 77 69 66 51 57 62 54 47 51 62 62 65 77 Year 2005 2008 2007 2003 2002 2008 2006 2005 2005 2004 2006 2006 8/1/05 Gale days 2.6 1.4 1.2 0.0 0.1 0.1 0.0 0.0 0.0 0.6 1.4 1.4 8.8 Days with ..