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eurec4a / how_to_eurec4a

Code examples to get you started with EUREC⁴A data.
https://howto.eurec4a.eu
MIT License
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correlate rttov channels and GOES-16 ABI channels #97

Open felix-mue opened 1 year ago

felix-mue commented 1 year ago

The rttov data contains contains 7 variables called "synsat_rttov_forward_model_1abi_ir__goes_16channel_1" through "..._channel7". As far as I understand the process to calculate brightness temperatures from ABI channels as outlined in the GOES-16 ATBD uses 7 channels (with an additional one for backup). I assume that the 7 rttov channels are the model data of these 7 channels in ABI.

But how do I know which channel in the rttov data corresponds to a certain channel from ABI?

observingClouds commented 1 year ago

Thanks @felix-mue for posting your question. This is indeed not very well documented at the moment. Currently you need to add 6 to the channel number in the variable name to get the equivalent GOES16-ABI channel. synsat_rttov_forward_model_1__abi_ir__goes_16__channel_1 emulates GOES16-ABI channel 7 synsat_rttov_forward_model_1__abi_ir__goes_16__channel_2 emulates GOES16-ABI channel 8 ... These values are already brightness temperatures.

For each channel, RTTOV applies the spectral response function from the actual ABI instrument. [https://nwp-saf.eumetsat.int/downloads/rtcoef_rttov13/ir_srf/rtcoef_goes_16_abi_srf.html] gives you a very detailed overview about the frequency range that is covered by each channel.

I will likely rename the variables in the dataset. However, I hope this helps you for now to keep coding 🤓

felix-mue commented 1 year ago

Fantastic, thanks a lot!