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zxdawn / S5P-LNO2

Core code for the TROPOMI lightning NO2 retrievals
GNU General Public License v3.0
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LNO2 is lower than LNO2Vis #54

Closed zxdawn closed 2 years ago

zxdawn commented 2 years ago

Because the LNO2Vis the NO2 above the cloud, it should < LNO2. However, it's larger:

image

zxdawn commented 2 years ago

The background NO2 can be negative in the Arctic, thus the missing step of removing background NO2 leads to the larger LNO2:

https://github.com/zxdawn/S5P-LNO2/blob/587780b2ca8c74ccf06cca6949c0bf154847c086/main/s5p_lno2_product.py#L177

https://github.com/zxdawn/S5P-LNO2/blob/587780b2ca8c74ccf06cca6949c0bf154847c086/main/s5p_lno2_product.py#L295

The LNO2 should be:

lno2 = (ds_amflno2['no2Trop']*amf_lno2 - scd_no2_bkgd) / amf_lno2