Drought and Dry Spells

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Paul C
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Drought and Dry Spells

Post by Paul C » Tue Jul 16, 2013 9:29 pm

Darren - I think this one is for you !

What do you think, are we approaching one now

No Rainfall here for 10 days, last rainfall more than 1mm was 4th July

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Re: Drought and Dry Spells

Post by darrog » Wed Jul 17, 2013 9:39 am

the 16th made the 13th successive day of no rain (trace on 4th so included in those 13 days) so just two days left to go to have an absolute drought.
people will argue over what is a drought and obviously the best definition is the hydrological one, but obviously we use meteorological terms.

Always an interesting one, because whilst I have done some research into droughts and wet spells, etc, you still need to have the daily data to know when they happened and the time period.
But my own opinion is that even here in Cumbria we are still more likely to have a drought (absolute or partial) than we are a rain or wet spell.
Even here at MM since my rainfall data began 06/07 droughts far outweigh rain and wet spells - see below.


DROUGHTS AND DRY SPELLS:-

1.) ABSOLUTE DROUGHT
23.03.13. - 10.04.13. 19 days - 0.3 mm (actually included x3 days of 0.1 mm and x8 of 'trace' - but none of 0.2 mm)

18.03.12. - 01.04.12. 15 Days of no recordable rain.

12.05.08. - 26.05.08. 15 Days of no recordable rain.


2.) PARTIAL DROUGHT
06.04.11. - 04.05.11. 29 Days - 1.8 mm

07.04.10. - 05.05.10. 29 Days - 3.2 mm




3.) DRY SPELLS
14.02.13. - 05.03.13. 20 days - 1.4 mm

11.04.10. - 27.04.10. 17 Days - 1.2 mm

27.02.10. - 17.03.10. 19 Days - 1.8 mm

09.09.09. - 01.10.09. 23 Days - 0.6 mm

10.04.09. - 24.04.09. 15 Days - 0.4 mm

21.12.08. - 05.01.09. 16 Days - 0.9 mm

19.08.07. - 14.09.07. 27 Days - 1.8 mm


1.) ABSOLUTE DROUGHT - Period of at least 15 consecutive days to none of which is credited 0.2mm (0.01 inch) of ppt
2.) PARTIAL DROUGHT - Period of at least 29 consecutive days whose mean daily ppt does not exceed 0.2mm
3.) DRY SPELL - Period of at least 15 consecutive days to none of which is credited 1.0mm (0.04 inch) of ppt


RAIN SPELLS AND WET SPELLS:-


1.) WET SPELL
23.11.11. - 08.12.11. 16 Days - 148.5 mm

12.11.09. - 29.11.09. 18 Days - 241.0 mm


2.) RAIN SPELL
22.12.11. - 06.01.12. 16 Days - 89.7 mm

23.11.11. - 20.12.11. 28 Days - 207.9 mm

14.08.09. - 04.09.09. 22 Days - 120.2 mm

1.) WET SPELL - a period of at least 15 consecutive days to each of which is credited 1.0 mm (0.1 inch) of ppt
2.) RAIN SPELL - a period of at least 15 consecutive days to each of which is credited 0.2 mm (0.01 inch) of ppt



But then take Orton (near Tebay) which despite being only five miles from me is much wetter and the periods of drought from 1981 are shown below. Absolute droughts far outweigh the number of partial droughts, thus demonstrating the rarity of 29 successive settled days, at least in Orton.


1.) ABSOLUTE DROUGHT
18.03.12. - 01.04.12. 15 Days of no recordable rain

12.05.08. - 26.05.08. 15 Days " " " "

03.04.07. - 18.04.07. 16 Days " " " "

21.05.97. - 04.06.97. 15 Days " " " "

25.04.95. - 11.05.95. 17 Days " " " "

21.06.95. - 05.07.95. 15 Days " " " "

06.06.92. - 29.06.92. 24 Days " " " "

28.08.91. - 12.09.91. 16 Days " " " "

19.11.89. - 05.12.89. 17 Days " " " "

04.06.88. - 20.06.88. 17 Days " " " "

06.09.86. - 26.09.86. 21 Days " " " "

11.10.85. - 29.10.85. 19 Days " " " "

08.08.84. - 27.08.84. 20 Days " " " "

26.07.83. - 14.08.83. 20 Days " " " "

09.04.82. - 27.04.82. 19 Days " " " "

16.07.82. - 30.07.82. 15 Days " " " "

23.08.81. - 06.09.81. 15 Days " " " "

I have yet to have a July drought, but then Orton has not had one for 30 yrs and no summer drought since 1995!
But then a rogue shower of 0.2mm will prevent an absolute drought.
And somewhat unsurprisingly the Spring is the driest time of the year and most likely time to have a drought.

If no-one lese has recorded their own droughts/wet spells, etc then I would recommend that you do, it is worthwhile, maybe something to do this winter.
Darren Rogers - he who submits the most interesting posts, AKA Mr Data
Maulds Meaburn

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Re: Drought and Dry Spells

Post by Carl M » Wed Jul 17, 2013 10:13 am

Interesting, I need to go through my own data.
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Re: Drought and Dry Spells

Post by Paul C » Wed Jul 17, 2013 8:20 pm

I knew you would have had something listed Darren - good effort. :) :) zz

As you say something for the winter months perhaps

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Re: Drought and Dry Spells

Post by darrog » Wed Jul 17, 2013 9:18 pm

Paul - haven't you kept a record?
Darren Rogers - he who submits the most interesting posts, AKA Mr Data
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Re: Drought and Dry Spells

Post by Paul C » Thu Jul 18, 2013 10:06 pm

I havent ! and this very amiss of me

Its strange as I should really, not sure where to start now.

In an ideal world, I wonder what records we should keep ?

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Re: Drought and Dry Spells

Post by darrog » Thu Jul 18, 2013 11:52 pm

apart from absolute and partial droughts, dry spells, rain spells and wet spells, the following:

TEMPERATURE
Highest Temp'
Lowest Temp'
Highest Minimum
Lowest Maximum
Grass - Lowest
Grass - Latest (Spring) frost
Grass - Earliest (Autumn) frost
Grass - Most consecutive
Highest Monthly Mean
Lowest Monthly Mean
Earliest (Spring) 20°
Latest (Autumn) 20°
Earliest (Autumn) frost
Latest (Spring) frost
Earliest (Autumn) Ice Day
Latest (Spring) Ice Day
Most consecutive days of Max' 20.0°>=
Most consecutive days of Min' =<0.0°
Widest daily range
Longest period below freezing


RAIN

Wettest day
Rain Rate
Wettest month
Driest month
Driest wettest day of any month
Month with most 'Rain days'
Month with least 'Rain days'
Most consecutive 'Rain Days'
Most consecutive days of no rain


WIND

Highest Gust
Highest Daily Mean
Highest Monthly Mean


BAROMETRIC PRESSURE

Highest
Lowest
Highest monthly mean at 0900 hrs
Lowest monthly mean at 0900 hrs


SNOWFALL

Most consecutive days of laying snow
Greatest (level) depth
Earliest (Autumn) snowfall
Earliest (Autumn) day of laying snow
Latest (Spring) snowfall
Latest (Spring) day of laying snow


THE TOP TEN

HIGH MAX

LOW MAX

LOW MIN

HIGH MIN

WETTEST DAY
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Re: Drought and Dry Spells

Post by Paul C » Sat Aug 03, 2013 8:16 pm

Looks like i will be busy this winter !

Anyway I have found something that I did a while ago
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