README.md

Septoria reference humidity model - spatial version

The reference humidity model was developed as a supplement to the Humidity model. In this model 20 consecutive hours are required to fulfil a risk period. One constraint in this method is that you can have 19 consecutive risk hours or,
fx 14 hours with risk then one hour below the Rh threshold and then maybe 14 hours again with risk hours. In one of these situations, the model will indicate a risk. In the reference model the definition of Humid hours was introduced. The Rh threshold was avoided as humid hours do not need to be consecutive. The running sum of humid hours across three days indicate that the Septoria risk is higher than if you have three days with humid conditions than two or one. The operation of the model should include weather forecast data and should run 6 days ahead from current day if you include a 7-day weather forecast (60 hours from national met office and until 7 days from ECMWF)

The model was tested against the Humidity model in a Danish Septoria project funded by the GUDP. The threshold of 40 was defined as high risk as this coincided with periods when the humidity model recommended to apply fungicide (if not already protected). The humidity model includes a decision model about when to spray, protection periods ect. The reference model was used to quality control the recommendations in a way that, if the reference humidity hours were higher than 40 (no thresholds) then the user should check the raw data for calculation of the Humidity model (threshold, 20 consecutive hours). If 2-3 periods of 17, 18, or 19 consecutive hours appear, then one can consider to protect the crop based on the reference model alone.

The Humidity model is considered as a DSS with several components. The reference humidity model is considered as a weather based submodel for the risk of Septoria, Easy to map and calculate based on weather data alone.<

Notes to self

Converting variables in NetCDF to GeoTIFF

Given the one-timestep weather datafile analysis-2023-10-08_1.nc, this command:

gdal_translate -of GTiff -sds   analysis-2023-10-08_1.nc test.tif

...produces 7 tiff files (test_1.tif ... test_7.tif) that each represent one variable from the NetCDF file. The first two are latitude and longitude, then the weather data variables.

The files can be merged using gdal_merge.py, like this:

gdal_merge.py -separate in/test_3.tif in/test_4.tif in/test_5.tif in/test_6.tif in/test_7.tif

Could we live with x GeoTIFF files per timestamp, where x is the number of variables?