TVDI

gma.rsvi.TVDI

function TVDI(vi, lst, vi_range = [0.2, 0.8], lst_range = [200, 350], delta = 0.01, vi_nodata = None, lst_nodata = None, out_nodata = -1.0):

Calculate the Temperature Vegetation Drought Index.

Parameters:

vi: array.

Vegetation index data.

lst: array.

Land surface temperature (K).

Optional:

vi_range = list. Default [0.2, 0.8].

Valid value range of vegetation index participating in wet and dry edge fitting.

lst_range = list. Default [200, 350].

Valid value range of land surface temperature participating in wet and dry edge fitting.

delta = float. Default 0.01.

The sample spacing for vegetation index sampling during wet and dry edge fitting.

vi_nodata = float. Default None.

Invalid value in vegetation index data.

lst_nodata = float. Default None.

Invalid value in land surface temperature data.

out_nodata = float. Default -1.0.

Invalid values in TVDI results. The value of the corresponding position of vi_nodata and lst_nodata will also be changed to out_nodata.

Returns:

Type: namedtuple.

TVDI: TVDI results.

x_vi: VI involved in fitting.

wet_lst: Wet edge LST involved in fitting.

dry_lst: Dry edge LST involved in fitting.

wet_a: Wet side equation coefficients.

wet_b: Wet side equation constants.

dry_a: Dry side equation coefficients.

dry_b: Dry side equation constants