Daily snow water equivalent product with SMMR, SSM/I and SSMIS from 1980 to 2020 over China

Figures & data

Figure 1. Spatial distribution of (a) meteorological stations and field snow courses; (b) land use types over China.

Table 1. The main parameters measured along these four snow survey courses (conducted from December 2017 to May 2019).

Snow course	Air temperature (°C)		Snow depth (cm)		Snow density (kg/m3)		samples
	max	min	max	min	max	min
1	–2.5	–34.0	40	3	285	98	92
2	–1.3	–29.5	66	1	410	118	119
5	–1.8	–32	51	2	370	88	126
6	−3	−32	46	2	263	128	59

Table 2. Summary of the main passive microwave remote sensing sensors. The letter “A” and “D” represent ascending and descending, respectively.

Sensor	SMMR	SSM/I			SSMIS
Satellite	Nimbus-7	DMSP-F08	DMSP-F11	DMSP-F13	DMSP-F17
On orbit time	1978–1987	1987–1991	1991–1995	1995–2008	2006-present
Revisit period	every two days	daily
Passing time	A: 12:00 D: 24:00	A: 06:20 D: 18:20	A: 17:17 D: 05:17	A: 17:58 D: 05:58	A: 17:31 D: 05:31

Table 3. The information of the SWE product provided by this paper.

File Name	Variable	Unit	Effective Value	Quality Identifier
SATELLITE_SENSOR_SWE_YYYYMMDD_DAILY_025KM_V1.2.h5	SWE	mm	0–240	250: dry snow
	SD	cm	0–100	251: wet snow
	Latitude	degree	16°N–56°N	252: free snow/
	Longitude	degree	72°E–142°E	253: water & building/
				254: no data
				255: outside China
SATELLITE_SENSOR_SWE_YYYYMMDD_DAILY_025KM_V1.2.png	quick-view of SWE

Figure 2. Comparison of SWE estimates and weather station measurements.

Figure 3. Time series (2011–2019) comparison between measured and estimated snow depth data.

Figure 4. Validation of snow depth product with field snow course data during the period 2018–2019.

Figure 5. Spatial distribution of annual (a) averaged SWE and (b) snow cover days (SCD) during the period 1980–2018.

Figure 6. Spatial distribution of annual (a) SWE and (b) SCD trends from 1980 to 2018 based on slope test. Only areas with trends having a significance level exceeding 95% are shown.

Figure 7. Annual average SWE series of China from 1980 to 2018. Dashed lines represent regression lines of the corresponding SWE series. Trends were considered significant if p < 0.05.