# PARAMETERS OF GLOBAL SURFACE SOIL MOISTURE DRYDOWN USING SMAP

### Data description
- The parameters for the global soil moisture drydown pathways (Sehgal et. al. 2020) are provided as Comma Separated Values (CSV) and global raster format.
- Data is provided separately for the four seasons (*DJF, MAM, JJA and SON*) and combined total data (*all data*). 
- Missing values are indicated with “**NA**” in the CSV file.

### Variables
|SlNo	| Name		| Description                                              	| Unit
|------	|-----------	|-------------							|---	
| 1	|longitude	|Longitude of SMAP pixel centroid				|Decimal degree
| 2	|latitude	|Latitude of SMAP pixel centroid				|Decimal degree
| 3	|canonical_form	|Canonical shape of drydown using non-parametric approach	|NA
| 4	|pathway	|Drydown pathway using non-linear least-squares fitting		|NA

# Parameters
| 5       | ld		|constant-rate loss during dry phase				|m3/m3/day
| 6       | theta_TD	|transition point between transitional and dry phase		|m3/m3
| 7       | m2		|slope of transitional phase					|day-1
| 8       | theta_WT	|transition point between wet and transitional phase		|m3/m3
| 9       | lw		|constant-rate loss during wet phase				|m3/m3/day
| 10      | theta_GW	|transition point between gravity drainage and wet phase	|m3/m3
| 11      | m1		|slope of gravity drainage phase				|day-1

# Uncertainty
| 12      | sd_ld	|standard deviation for ld		|m3/m3/day
| 13      | sd_theta_TD	|standard deviation for theta_TD	|m3/m3
| 14      | sd_m1	|standard deviation for m1		|day-1
| 15      | sd_theta_WT	|standard deviation for theta_WT	|m3/m3
| 16      | sd_lw	|standard deviation for lw		|m3/m3/day
| 17      | sd_theta_GW	|standard deviation for theta_GW	|m3/m3
| 18      | sd_m2	|standard deviation for m2		|day-1

# Performance
| 19      | MSE_val	|Mean squared error for validation dataset			|m6/m6/day2
| 20      | CC_val	|Correlation coefficient for validation dataset			|dimensionless
| 21      | d_val	|Index of agreement for validation dataset			|dimensionless
| 22      | replacement	|Is pathway replaced with a simpler form? (Yes= 1 or no=0)	|NA


**Reference**:
Sehgal, V., Gaur, N., & Mohanty, B. P. (2020). Global Surface Soil Moisture Drydown Patterns. Water Resources Research, 56, e2020WR027588. https://doi.org/10.1029/2020WR027588

**Contact**:
Vinit Sehgal, Water Management and Hydrological Science, Texas A&M University, TX 77840, USA, vinit@tamu.edu | vinit1263.09@gmail.com