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Correlation matrix of climate parameters and environment and human drivers with vegetation indicators in Tian Shan ecoregions
| Parameters | NDVI | EVI | LST | Total precipitation | Soil moisture | Actual evapotranspiration | DSR | Air temperature at 2 m | PDSI | Run off | Snow water equivalent | Wind speed |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NDVI | 1.0000 | |||||||||||
| EVI | 0.9916 | 1 | ||||||||||
| LST | 0.1906 | 0.220 | 1.000 | |||||||||
| Total precipitation | 0.0445 | 0.044 | −0.310 | 1 | ||||||||
| Soil moisture | −0.5839 | −0.570 | −0.540 | 0.6417 | 1.0000 | |||||||
| Actual evapotranspiration | 0.2264 | 0.224 | −0.260 | 0.9432 | 0.5336 | 1.0000 | ||||||
| DSR | −0.2708 | −0.250 | 0.131 | −0.5924 | −0.2929 | −0.6113 | 1 | |||||
| Air temperature at 2 m | 0.0356 | 0.033 | 0.078 | 0.3486 | 0.2616 | 0.4683 | −0.06 | 1 | ||||
| PDSI | −0.0959 | −0.120 | −0.490 | 0.7763 | 0.7336 | 0.7659 | −0.58 | 0.2533 | 1.000 | |||
| Run off | 0.0028 | −0.010 | −0.320 | 0.9294 | 0.7070 | 0.8968 | −0.58 | 0.3969 | 0.849 | 1.0000 | ||
| Snow water equivalent | 0.2833 | 0.244 | −0.090 | 0.4135 | 0.1860 | 0.4148 | −0.37 | −0.0506 | 0.468 | 0.4471 | 1.0000 | |
| Wind speed | −0.3068 | −0.320 | −0.040 | 0.1184 | 0.3789 | 0.0295 | −0.25 | −0.0102 | 0.207 | 0.2473 | 0.1736 | 1.0000 |
Correlation value and effect size
| Correlation value (r) | Level |
|---|---|
| −1.0 | Perfectly negative |
| −0.8 | Strongly negative |
| −0.5 | Moderately negative |
| −0.2 | Weakly negative |
| 0.0 | No association |
| 0.2 | Weakly positive |
| 0.5 | Moderately negative |
| 0.8 | Strongly positive |
| 1.0 | Perfectly positive |
17 ecoregions of Xinjiang province_ The area of all three Tian Shan ecoregions is well calculated_
| Ecoregions | Area, km2 | Percent |
|---|---|---|
| Alashan Plateau semi-desert | 67 | 16.498 |
| Altai alpine meadow and tundra | 90,434 | 2.212 |
| Altai montane forest and forest steppe | 142,875 | 3.495 |
| Altai steppe and semi-desert | 83,192 | 2.035 |
| Central Tibetan Plateau alpine steppe | 629,190 | 15.393 |
| Emin Valley steppe | 65,135 | 1.594 |
| Junggar Basin semi-desert | 304,938 | 7.460 |
| Karakoram-West Tibetan Plateau alpine steppe | 143,265 | 3.505 |
| North Tibetan Plateau-Kunlun Mountains alpine desert | 374,494 | 9.162 |
| Pamir alpine desert and tundra | 118,072 | 2.889 |
| Qaidam Basin semi-desert | 192,147 | 4.701 |
| Rock and Ice | 34,830 | 0.852 |
| Taklimakan desert | 742,657 | 18.169 |
| Tarim Basin deciduous forests and steppe | 54,533 | 1.334 |
| Tian Shan foothill arid steppe | 129,231 | 3.162 |
| Tian Shan montane conifer forests | 27,568 | 0.674 |
| Tian Shan montane steppe and meadows | 280,611 | 6.865 |
Correlation matrix of human parameters and vegetation cover index of Tian Shan ecoregions
| Parameters | EVI | NDVI | DMSP | CNLI |
|---|---|---|---|---|
| EVI | 1 | |||
| NDVI | 0.9940 | 1 | ||
| DMSP | 0.7259 | 0.7388 | 1 | |
| CNLI | 0.7349 | 0.7480 | 0.9995 | 1 |
Pearson correlation between vegetation indices
| Parameter | Value |
|---|---|
| Pearson correlation coefficient (r) | 0.991 |
| P-value | 0.000 |
| Covariance | 0.000 |
| Sample size (n) | 23.000 |
| Statistic | 35.122 |
Area and percentage and classifications of LULC
| Value | Description (LULC 2001) | Year 2001 | Year 2021 | ||
|---|---|---|---|---|---|
| area (km2) | percent | area (km2) | percent | ||
| 0 | Water bodies: at least 60% of area is covered by permanent water bodies | 554.99 | 0.25 | 563.78 | 0.250 |
| 1 | Evergreen Needleleaf Forests: dominated by evergreen conifer trees (canopy >2m). Tree cover >60%. | 41.51 | 0.01 | 21.05 | 0.009 |
| 5 | Mixed Forests: dominated by neither deciduous nor evergreen (40–60% of each) tree type (canopy >2m). Tree cover >60% | 248.60 | 0.11 | 173.45 | 0.070 |
| 9 | Savannas: tree cover 10–30% (canopy >2m) | 334.55 | 0.15 | 102.25 | 0.040 |
| 10 | Grasslands: dominated by herbaceous annuals (<2 m) | 142,376.59 | 65.28 | 506.15 | 0.230 |
| 11 | Permanent wetlands: permanently inundated lands with 30–60% water cover and >10% vegetated cover | 344.95 | 0.15 | 145,028.79 | 66.540 |
| 12 | Croplands: at least 60% of area is cultivated cropland | 16,810.66 | 7.70 | 83.62 | 0.030 |
| 13 | Urban and built-up lands: at least 30% impervious surface area including building materials, asphalt, and vehicles | 92.25 | 0.04 | 17,376.65 | 7.970 |
| 14 | Cropland/natural vegetation mosaics: mosaics of small-scale cultivation 40–60% with natural tree, shrub, or herbaceous vegetation | 40.74 | 0.01 | 61.50 | 0.020 |
| 15 | Non-vegetated lands: at least 60% of area is non-vegetated barren (sand, rock, soil) or permanent snow and ice with less than 10% vegetation | 1,754.22 | 0.80 | 156.22 | 0.070 |
| 16 | Barren: at least 60% of area is non-vegetated barren (sand, rock, soil) areas with less than 10% vegetation | 55,469.53 | 25.43 | 2,368.31 | 1.080 |
Relationship between climate and environmental variables with NDVI using Pearson regression model
| Parameters | P-value | r | Covariance | T | N | |
|---|---|---|---|---|---|---|
| NDVI | LST | 0.380 | 0.190 | 0.002 | 0.089 | 23 |
| Total precipitation | 0.840 | 0.044 | 0.001 | 0.089 | ||
| Soil moisture | 0.003 | −0.588 | −0.121 | −3.299 | ||
| DSR | 0.211 | −0.277 | −0.070 | −1.289 | ||
| Air temperature at 2 m | 0.871 | 0.035 | 0.000 | 0.163 | ||
| PDSI | 0.663 | 0.095 | −0.202 | −0.441 | ||
| Runoff | 0.989 | 0.002 | 0.000 | 0.013 | ||
| Snow water equivalent | 0.190 | 0.283 | 0.016 | 1.353 | ||
| Wind speed | 0.154 | −0.306 | −0.026 | −1.447 | ||
| Actual evapotranspiration | 0.298 | 0.226 | 0.046 | 1.065 |
Pearson correlation between NDVI and mean DMSP
| Parameter | DMSP | CNLI |
|---|---|---|
| Pearson correlation coefficient (r) | 0.73800 | 0.748 |
| P-value | 0.04800 | 0.043 |
| Covariance | 0.02241 | 0.034 |
| Sample size (n) | 7 | 7 |
| Statistic | 2.45100 | 2.520 |
Statistics related to human drivers from 2000 to 2020 using advanced sensors and night data extraction
| Year | Mean value | Sum (S) | Total sum | Mean (zonal statistic) | Light index (%) | CNLI (%) |
|---|---|---|---|---|---|---|
| DMSP NTL 2000 | 0.2365 | 8,959 | 342,016 | 8.78 | 23 | 0.36 |
| DMSP NTL 2005 | 0.3348 | 12,394 | 342,016 | 9.10 | 33 | 0.52 |
| DMSP NTL 2010 | 0.5766 | 23,919 | 342,000 | 8.15 | 57 | 0.90 |
| DMSP NTL 2015 | 1.7730 | 79,304 | 342,016 | 7.33 | 17 | 2.60 |
| DMSP NTL 2018 | 3.9763 | 184,971 | 342,016 | 7.34 | 39 | 6.30 |
| DMSP NTL 2019 | 7.2632 | 317,604 | 342,016 | 7.75 | 72 | 11.00 |
| DMSP NTL 2020 | 2.1115 | 79,180 | 342,016 | 9.11 | 21 | 3.34 |
Relationship between climate and environmental variables with EVI using Pearson regression model
| Parameters | P-value | r | Covariance | T | N | |
|---|---|---|---|---|---|---|
| EVI | LST | 0.311 | 0.219 | 0.000 | 1.023 | 23 |
| Total precipitation | 0.840 | 0.043 | 0.000 | 0.201 | ||
| Soil moisture | 0.003 | −0.577 | −0.074 | −3.021 | ||
| DSR | 0.247 | −0.251 | −0.041 | −1.185 | ||
| Air temperature at 2m | 0.188 | 0.032 | 0.000 | 0.150 | ||
| PDSI | 0.597 | 0.116 | −0.153 | −0.536 | ||
| Runoff | 0.979 | 0.055 | 0.000 | 0.155 | ||
| Snow water equivalent | 0.262 | 0.243 | 0.009 | 1.152 | ||
| Wind speed | 0.142 | −0.315 | −0.016 | −1.522 | ||
| Actual evapotranspiration | 0.305 | 0.223 | 0.038 | 1.051 |
Vegetation anomalies and changes during the period from 2000 to 2022
| Description of the changes | Area (km2) |
|---|---|
| No vegetation (unchanged) | 120,032.63 |
| Deforestation | 7,190.12 |
| Afforestation | 12,089.28 |
| Vegetation (unchanged) | 78,733.91 |
Main sources with the satellite product specifications
| Insignia | Product | Parameter | Temporal coverage | Description | Website details | |
|---|---|---|---|---|---|---|
|
| MYD13A1.0 61 | NDVI | 16 Daily | Normalized Difference Vegetation Index | https://developers.google.com/earth-engine/datasets/catalog/MODIS_061_MYD13A1 | |
|
| ERA5-Land | Temperature | Daily | ECMWF Climate Reanalysis | https://developers.google.com/earth-engine/datasets/catalog/ECMWF_ERA5_LAND_DAILY_AGGR#bands | |
| Evaporation | ||||||
| Runoff | ||||||
|
| CHIRPS | Precipitation | Daily | Hazards Group InfraRed | https://developers.google.com/earth-engine/datasets/catalog/UCSB-CHG_CHIRPS_DAILY | |
| Product | Band | Image collection | Value | Units | Time and dataset availability | |
| Min | Max | |||||
| MYD13 A1.061 | NDVI | MODIS/061/MYD13A1 | -2000 | 10000 | -- | 2002-07-04T00:00:00Z–2023-06-18T00:00:00 |
| ERA5-Land | temperature_2m | ECMWF/ER A5_LAND/D AI LY_AGGR | -- | -- | K | 1950-01-02T00:00:00Z–2023-07-26T00:00:00 |
| total_evapora | -- | -- | m of water equivalent | |||
| tion_sum | ||||||
| runoff_sum | -- | -- | m | |||
| CHIRPS | Precipitation | CSB-CHG/CHIRPS/DAILY | 0* | 1444.34* | mm/d | 1981-01-01T00:00:00Z–2023-06-30T00:00:00 |
| Satellite/model | Product name | Data name | Unit | Spatial resolution | Temporal resolution | Time extent |
| Modis/Terra | MOD11A1.0 61 Terra Land Surface Temperature and Emissivity Daily Global 1 km | LST_Day_1km | Kevin | 1000 meters | Daily | 2000-02-24 |
| Modis/Terra | Vegetation Indices | NDVI | - | 500 meters | Daily | 2000-02-18 |
| FLDAS | FEWS NET | Soil Moisture | m^3 | 10 km | Monthly | 1/1/1982 |
| Shortwave Radiation Flux | w m-2 | -- | -- | |||
| TERRA Climate | University of IDAHO | Palmer Drought Index | nan | -- | -- | 1/1/1958 |
| Wind Speed | m/s | 4 km | Monthly | |||
| Satellite/model | Product name | Date name | Unit | Spatial resolution | Temporal coverage | Time extent |
| MODIS | MODIS Land Cover Type (LC_Type2 Class Table) | MCD12Q1.06 1 | - | 500 m | Yearly | 2001-01-01T00:00:00Z–2022-01-01T00:00:00 ee.ImageCollection("MODIS/061/MCD12Q1") |