im currently doing research on distribution of rainfall at Peninsular Malaysia. Then, i only had daily rainfall data. However, i want to Classes Rainfall Intensity. Then, all the class for Rainfall Intensity is based on mm/hr. but i only had a daily data.
So, may i know how can i classify this Rainfall Intensity in mm/day?
Dear Deana,
If you have daily precipitation and want to convert it to hourly, you need to know the common temporal distribution of hyetograph in your region and also number of rainfall events per each single day.
If you assume that your daily precipitations are fallen during single events, it means that for each day, the area under your hyetograph should be same as the height of your precipitation.
Regards
Mo
I assume you want to obtain a time series at an hourly timestep (otherwise, all you are doing is changing the units, which is trivial - divide by 24). It is impossible to do this using daily data as the information has been lost. The best you can do is get an estimate of the hourly rainfall (with considerable uncertainty), but only if you have additional information.
You can follow the approach described by Mohammad, but this will only give you an estimate of the hourly rainfall based on an average event duration, and will not reproduce the event-to-event variations that will be present. You could use a weather generator to convert each day's rainfall into hourly amounts, but you need to define the parameters used by the weather generator.
You can use a data mining approach to find a relationship between types of weather events and other climatic data you have available, but this needs hourly (or sub-hourly) rainfall data for somewhere in the region. If you have this you might be able to better capture the event-to-event variations, but there will still be considerable uncertainty.
If you need hourly rainfall for particular days, then you are stuck, and need to either find an additional data source (e.g. satellite derived rainfall) or change what you are trying to do. Since you haven't said what this is for, I can't advise further.
hi Mohammad, thank you for your suggestion but i think if i need a lots of others metadata to support or to convert my data from mm/day to mm/hr.
hi Barry,
regarding your answer, now i think i need to change from trying to change mm/day to mm/hr. as i actually trying to do spatial distribution of rainfall on a region using the rainfall intensity but however most of the journal i found the rainfall intensity were in mm/hr where i just had a daily data only.
after i trying alots of method to change mm/day to mm/hr and read your idea and answer, i agree with you. i cannot simply change mm/day to mm/hr as this will give alots of argument
lastly, i found a method on how to just using rainfall intensity in mm/day to describe the spatial distribution of rainfall on my region as i found a journal about spatial distribution using rainfall intensity in mm/day.
tq
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