=== versions === python 3.12.0 | numpy 2.5.4 | scipy 1.18.1 | pandas 3.1.0 | rasterio 1.5.2 | pystac-client 0.9.1 === Step 1: COSMOS-UK daily soil moisture and rainfall === site name cover days cosmos_vwc_min cosmos_vwc_max tdt_10cm_min tdt_10cm_max rain_mm WIMPL Wimpole arable 731 20.4 56.4 17.6 46.9 1301 ROTHD Rothamsted arable 731 15.0 44.5 19.2 43.3 1562 CARDT Cardington grassland 731 10.2 37.3 11.5 44.7 1409 WADDN Waddesdon grassland 731 21.7 56.7 14.8 47.9 1490 === Step 2: Sentinel-1 RTC VV time series over each station footprint === read in 23.4 s WIMPL (Wimpole, arable): 165 acquisitions count mean std min max orbit pass 59 ascending 59 -8.88 1.69 -11.87 -5.87 81 descending 52 -9.47 1.63 -12.82 -6.51 132 ascending 54 -9.75 1.54 -13.13 -6.42 ROTHD (Rothamsted, arable): 106 acquisitions count mean std min max orbit pass 81 descending 52 -9.64 1.75 -13.01 -5.56 132 ascending 54 -9.53 1.54 -13.52 -6.47 CARDT (Cardington, grassland): 154 acquisitions count mean std min max orbit pass 81 descending 52 -12.06 0.66 -13.37 -9.82 132 ascending 54 -11.79 0.91 -13.49 -7.76 154 descending 48 -11.88 0.65 -13.34 -10.27 WADDN (Waddesdon, grassland): 216 acquisitions count mean std min max orbit pass 30 ascending 56 -11.63 0.89 -14.13 -9.96 81 descending 52 -11.58 1.02 -13.24 -9.45 132 ascending 54 -11.05 1.21 -13.43 -8.49 154 descending 54 -11.12 1.16 -13.51 -8.45 === Step 3: dry/wet references and relative surface soil moisture === site orbit dry_dB wet_dB sensitivity_dB WIMPL 59 -11.10 -6.18 4.92 WIMPL 81 -12.09 -6.69 5.39 WIMPL 132 -11.93 -7.36 4.58 ROTHD 81 -12.38 -7.23 5.14 ROTHD 132 -12.24 -7.32 4.92 CARDT 81 -12.94 -10.98 1.96 CARDT 132 -12.80 -10.46 2.34 CARDT 154 -12.74 -10.84 1.90 WADDN 30 -12.79 -10.18 2.61 WADDN 81 -13.12 -10.00 3.13 WADDN 132 -12.83 -9.17 3.66 WADDN 154 -13.12 -9.43 3.69 === Step 4: agreement with COSMOS-UK (Pearson r, same-day match) === site cover n r_cosmos r_tdt10cm r_pooled_orbits r_raw_dB r_Oct-Mar r_Apr-Sep rmse_vwc_% WIMPL arable 163 0.40 0.46 0.40 0.41 0.45 0.11 8.45 ROTHD arable 104 0.74 0.63 0.74 0.74 0.49 0.71 5.22 CARDT grassland 154 0.27 0.20 0.24 0.16 0.41 0.06 8.79 WADDN grassland 216 0.53 0.47 0.50 0.49 0.42 0.28 8.41 r_pooled_orbits: one dry/wet reference for all orbits (no incidence-angle handling) rmse_vwc_%: relative SSM rescaled to the station's 5th-95th percentile VWC range mean relative SSM (%) and COSMOS VWC (%) by rain in the previous 3 days: site n_rain>=10mm_3d ssm_after_rain n_no_rain_3d ssm_no_rain cosmos_after_rain cosmos_no_rain WIMPL 32 73.8 43 25.0 41.3 34.5 ROTHD 23 73.7 20 33.4 36.8 31.4 CARDT 26 65.6 17 27.9 28.4 23.8 WADDN 45 71.8 49 36.3 44.1 36.8 === Step 5: soil water index (exponential filter) vs COSMOS === site cover r_SSM r_SWI_T1 r_SWI_T5 r_SWI_T10 r_SWI_T20 r_SWI_T40 r_SWI_T60 WIMPL arable 0.40 0.41 0.47 0.51 0.55 0.57 0.55 ROTHD arable 0.74 0.74 0.80 0.84 0.84 0.79 0.73 CARDT grassland 0.27 0.28 0.38 0.46 0.55 0.64 0.65 WADDN grassland 0.53 0.54 0.66 0.72 0.78 0.80 0.77 best characteristic time length on average: T = 40 days === Step 6: 100 m relative soil moisture maps around Wimpole (orbit 81, descending) === 52 dates on a 120 x 120 grid of 100 m (100.0% valid); grassland+cropland = 87% of pixels median sensitivity (wet - dry) on cropland 7.68 dB, grassland 3.16 dB, tree cover 2.45 dB, built-up 2.64 dB case date COSMOS_vwc_% rain_prev_5d_mm median_SSM_cropland_% median_SSM_grassland_% dry 31 Aug 2024 22.5 0.0 38.2 29.3 wet (winter) 04 Jan 2024 47.8 38.1 95.9 83.9 wet (crops growing) 09 May 2023 56.4 51.3 27.4 68.6 area-median SSM (grass+crop) vs Wimpole COSMOS over 52 dates: r = 0.37 === Step 7: figures === saved 01-backscatter-orbits-wimpole.png, 02-ssm-vs-cosmos-timeseries.png, 03-scatter-by-season.png, 04-ssm-maps-wimpole.png, 05-correlation-summary.png total run time 38.6 s