Weather & Climate of Virginia

Transcription

1 Weather & Climate of Virginia Robert E. Davis Professor of Climatology Dept. of Environmental Sciences University of Virginia Rivanna Master Naturalists March 14, 2017

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3 Arctic Circle Tropic of Cancer

4 SEASONS

5 Effect of Solar Angle

6 circle of illumination Radiation receipt: 1) sun angle (intensity) 2) day length (duration)

7 Top of Atmosphere Sunlight Arctic 0 44 Charlottesville Equator 34 36

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9 Continentality Mean temperature of warmest minus coldest month

10 Incoming Outgoing

11 General Circulation of the Atmosphere

12 Ocean Circulation

13 Jet Stream: 1) Boundary between warm, tropical and cold, polar air masses cold 2) Size and strength vary seasonally 3) Linked to midlatitude storms at surface warm 4) Linked to storm tracks 5) A component of (circum)-polar vortex

14 Jet Stream (Polar Vortex) Patterns

15 JANUARY JULY COLD! COOL IN WINTER, JET STREAM 1) EXPANDS 2) STRENGTHENS earth_science/terc/content/ investigations/es1906/ es1906page02.cfm

16 A (Very) Short Course on Weather

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20 Storms are low pressure systems

21 L! Types of Fronts

22 Cold Front (vertical cross-section)

23 Warm Front (vertical cross-section)

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26 Cold Air Warm Air

27 Average January Winds North wind Richmond Southwest wind (color = speed)

28 Average July Winds North wind Richmond (color = speed)

29 July Mean Maximum Dew Point Temperature

30 Common Wind Directions Aloft Surface

31 Rain Shadow Effect

32 Mountain Effects (Elevation: 1000 feet) (Elevation: 3500 feet)

33 Charlottesville Precipitation thunderstorms hurricanes fronts

34 SUMMER

35 % Rainfall (May-Nov) from Tropical Cyclones Knight and Davis, 2007

36 Charlottesville Climatic Water Budget AE = Actual Evapotranspiration PE = Potential Evapotranspiration P = Precipitation millimeters

37 P PE Surplus

38 PE Deficit P

39 PHENOLOGY Study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life

40 PHRENOLOGY Study of the and size of the cranium as a (supposed) indication of character and mental abilities

41 Grape Phenology Light, heat accumulation, soil moisture

42 Organism Growth and Temperature growth begins growth at maximum

43 Growing Degree Days (GDDs) accumulated degrees over time above a baseline and below a maximum, based on daily mean temperature April 10: Max = 65, Min = 45, so Mean = 55; = 5 GDDs April 11: Max = 70, Min = 50, so Mean = 60; = 10 GDDs Season total = 15 GDDs

44 Growing Degree Days (GDDs) These vary by organism! corn baseline = 50 F lettuce baseline = 42 F potato baseline = 46 F

45 Growing Degree Days (GDDs) As of Sunday (3/12), CHO had accumulated 200 (corn) GDDs 140 above average for that date Cautions Some organisms are more light than heat sensitive, so GDDs will not be as useful Proper growth depends on adequate soil moisture as well as heat accumulation

46 Average Accumulated GDDs for Mar. 12

47 2017 Accumulated GDDs for Mar. 12

48 GDDs to Date Average

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50 Plant Hardiness Zones Average of each year s lowest minimum temperature

51 Plant Hardiness Zones

52 Hardiness Zone Changes

53 Average Date of Last Spring Frost Freeze Frost 6-Apr 17-Apr 22-Apr 6-May 23-Apr 5-May 6-May 17-May 25-Apr 11-May 27-Apr 8-May 6-May 18-May 2-May 17-May???????? 90 th percentile

54 Average Date of Last Spring and First Fall Frost Continental U.S. 6 4 Later Earlier Deviation from average (days) Long-term average Fall frost Spring frost Year (Kunkel, 2009)

55 Length of Growing Season, Continental U.S. 15 Deviation from average (days) Long-term average Year (Kunkel, 2009)

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57 Virginia Annual Temperatures Virginia Statewide Annual Temperature Temperature ( F) Year

58 Virginia Annual Precipitation:

59 Weather & Climate of Virginia Robert E. Davis Professor of Climatology Dept. of Environmental Sciences University of Virginia Rivanna Master Naturalists March 14, 2017

60 Here are some websites related to my presentation that might be of interest: Jet stream animation investigations/es1906/es1906page02.cfm Plant Hardiness maps Animation of current global winds, ocean currents, etc. orthographic=-43.14,8.77,356