after calculation of SEN'S SLOPE, i want to findout "%change" with the help of formula
I have a formula , " %change = (median slope * length of period) / mean"
In this case, i get a small confusion is what is the meaning of length of period and how much value i choose??
For example: I used to calculate 10 years data of rainfall
in this, what is the value i should take for LENGTH OF PERIOD for
And one more thing somebody's said for length of period is 1and total years(10)
what is the true??????
Dear Gopala Rao
I can not write 'right' or 'wrong' the method that you are using for calculation of percentage change of annual or monthly rainfall. See, here the percentage change will be either negative of positive. Now, question is what is the basis for calculation? It is better to calculate first the long-term average of annual and monthly rainfall for a particular region or area (where the weather station is located). Then percentage deviation (+ or -) for a particular year or month should be calculated. As a long-term average, you should use at least 30 years data. If the data is not available for long-term period, then you may calculate on the basis of available range, not mentioning long-term.
By this simple arithmetic method you may avoid median slope or length of period etc.
Hope this suggestion will help you.
Best wishes
KG Mandal
Thank you sir, for your reply but, my doubt is still not clear.
actually my original data length is 35 years .
Yes sir
i mentioned formula above, in that case i want length period value
DEAR GOPALA RAO 1) Calculate the long term average over the years,in this case 35 years.Then consider each particular year and see how it differred from the long term.You can now consider these changes as percentages.2) You calculate the long term average for each month over 35 years.Then take each month average and see how it differred from that of the long term,then caculate these changes as percentages.Best regards
Dear Friends
That is the calculation procedure I have suggested already.
KG Mandal
Dear KG Mandal Sir,
I calculated long term rainfall % for this formula but i got the value is 27%, 31%, 32%, 35%, 36% in positive for rcp 85 rcp 45 & rcp 26 ( MC and EC) and in rcp 2.6 (MC) value is -33%.
I am in confusing state. can you please clear my doubt in this regard. is this value in positive or negative is corrected or not?
can we mentioned the above values for Uttarakhand state will projected rainfall towards MC to EC.
%change = (median slope * length of period) / mean
Is median slope=Sen Slope? Please clarify
You are correct with the method of calculating the percentage change of rainfall, while the results will either positive (+) or negative (-).
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