## Minimum Insolation Over A Consecutive p-day Period

jwerstuik
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Joined: Thu Jul 23, 2020 3:17 pm America/New_York

### Minimum Insolation Over A Consecutive p-day Period

This parameter used to be given as a percentage and is defined as such:

Climatology: The minimum available insolation over a consecutive p-day period (p=1, 3, 7, 14, or 21 days) in a particular month is given as the % difference between the minimum monthly average value over the p-day period and the monthly average value for the p-day period. The p-day average is computed as a running average within each month. The monthly average for the p-day period is calculated as a multiyear average over the climatological period given in the header section of the data file.

Now the Unit is kW-hr/m^2/day.

How should we interpret this new unit? Is it the minimum cumulative amount of insolation expected over p-days? Is it the difference of cumulative insolation between minimum and average values over p-days? Or should we interpret this information differently.

Thank you,
Jeff

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ASDC - David W.
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### Re: Minimum Insolation Over A Consecutive p-day Period

GIS & POWER - mbroddle37
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### Re: Minimum Insolation Over A Consecutive p-day Period

Jeff,

Yes, there was a change in the consecutive p-day period parameters; we now provide the insolation value not a percentage. We have updated the parameter definitions to reflect this change.

The value is the cumulative minimum amount of insolation over the p-days period.

Since we now provide the insolation value, the percentage can be calculated following the example below:
INSOL_CONSEC_07_MIN / INSOL_CONSEC_07 = %

Thank you,

The NASA POWER Team
Prediction Of Worldwide Energy Resources (POWER)
NASA Earth Science/Applied Science Program
NASA Langley Research Center (LaRC)
POWER Documentation & FAQs

jwerstuik
Posts: 2
Joined: Thu Jul 23, 2020 3:17 pm America/New_York

### Re: Minimum Insolation Over A Consecutive p-day Period

In the Power Access application, if I wish to get the INSOL_CONSEC_07, which option should I select from the list?

When I select "Insolation Over A Consecutive p-day Period" I get INSOL_CONSEC_07 but it is described as "Surplus Insolation Over a Consecutive p-day Period" which is defined as:

"Available Surplus Insolation Over A Consecutive p-day period in a particular month is given as the irradiance value between the maximum monthly average value over the p-day period and the monthly average value for the p-day period. The p-day average is computed as a running average within each month. The monthly average for the p-day period is calculated as a multiyear average over the climatological period given in the header section of the data file."

Is this definition correct? Why would I divide by the surplus insolation between average a max when I am looking for the percentage difference between MIN and Average insolation over p-days?

ASDC - joseph.f.koch
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