Vegetation Water Research Articles

NDVI estimation using Sentinel-1 data over wheat fields in a semiarid Mediterranean region

ABSTRACT Annual crop monitoring is a key parameter for managing agricultural strategies. Several studies have relied on remote sensing products such as the normalized difference vegetation index (NDVI) as a vegetation dynamic metric. However, the dependence of optical data on weather conditions limits its availability. In this study, we reconstruct the NDVI time series of wheat fields using the moving averages of the Sentinel-1 normalized VH/VV cross-polarization ratio (IN) and the interferometric coherence in VV polarization over wheat selected fields in a semiarid site in Tunisia during two seasons, from 2018 to 2020. The crop cycle is divided into two periods: before and after the heading phase, which occurs in approximately the middle of March. Due to the volume-scattering impact, the second phase is divided into the ripening and maturation phase (NDVI ≥0.4) and senescence phase (NDVI <0.4). To estimate the NDVI values, different methods are used: curve-fitting equations and machine learning regressors such as the random forest (RF) and the support vector regressor (SVR). Low root mean square error (RMSE) values characterize NDVI estimation during the first period. In the second period, the RMSE values reach 0.06 when the NDVI is lower than 0.4. When the NDVI values exceed 0.4 in the second period, lower accuracy marks the NDVI estimation using the curve-fitting equations as a function of IN or coherence. Relative low accuracy characterizes the regression algorithms’ estimations when NDVI ≥ 0.4 compared to their performance during the aforementioned periods. The proposed approach was tested on different wheat fields. The NDVI estimations are characterized by RMSE values varying between 0.12 and 0.19. The use of RF and SVR outperformed the curve-fitting methods with an RMSE equal to 0.12. The present findings revealed the high accuracy of the proposed approach to estimate the missing values of wheat fields NDVI values during the vegetation development period until heading and the senescence phase. The presence of the mutual effect of the vegetation water content and its volume complicated the NDVI estimation using the C-band data.

Revealing the Hidden Consequences of Increased Soil Moisture Storage in Greening Drylands

Vegetation primarily draws water from soil moisture (SM), with restoration in drylands often reducing SM storage (SMS). However, anomalies have been detected in the Beijing–Tianjin Sand Source Region (BTSSR) of China via the Global Land Data Assimilation System (GLDAS) and Gravity Recovery and Climate Experiment (GRACE). This study quantified the sources of increased SMS in drylands to elucidate the effects of vegetation restoration on SMS. The results indicated the following: (1) In vegetated drylands, 46.2% experienced a significant increase in SMS while 53.8% remained stable; both were positively correlated with the normalised difference vegetation index (NDVI). (2) The increase in SMS was accompanied by a decrease in groundwater storage (GWS), as indicated by the significant correlation coefficients of −0.710 and −0.569 for SMS and GWS, respectively. Furthermore, GWS served as the primary source of water for vegetation. (3) The results of the redundancy analysis (RDA) indicated that the initial vegetation, the driver of the observed trend of increased SMS and decreased GWS, accounted for 50.3% of the variability in water storage. Therefore, to sustain dryland ecosystems, we recommend that future vegetation restoration projects give due consideration to the water balance while concurrently strengthening the dynamic monitoring of SMS and GWS.

Mechanism of Vegetation Greenness Change and Its Correlation with Terrestrial Water Storage in the Tarim River Basin

The response of dryland vegetation to climate change is particularly sensitive in the context of global climate change. This paper analyzes the characteristics of spatial and temporal dynamics of vegetation cover in the Tarim River Basin, China, and its driving factors in order to investigate the response of vegetation growth to water storage changes in the basin. The Enhanced Vegetation Index (EVI), the GRACE gravity satellite, and meteorological data from 2002 to 2022 are used to decipher the characteristics of the response of water storage changes to vegetation changes, which is of great significance to the realization of regional ecological development and sustainable development. The results of the study show the following: (1) The vegetation in the Tarim River Basin has an overall increasing trend, which is mainly distributed in the Aksu Basin and the Weigangkuche River Basin and is spatially distributed in the form of a ring. (2) Vegetation distribution greatly improved during the 20-year study period, dominated by high-cover vegetation, with a change rate of 200.36%. Additionally, vegetation changes are centered on the watersheds and expand to the surrounding area, with a clear increase in vegetation in the Kumukuri Basin. Areas with a vegetation Hurst index of &lt;0.5 account for 63.27% of the study area, and the areas with a continuous decrease were mainly located in the outer contour area of the Tarim River and Kumu Kuri Basins. (3) There are obvious spatial differences in the correlation between EVI and temperature and precipitation elements. The proportion of areas with positive correlation with temperature within the study area is 64.67%. EVI tends to be consistent with the direction of migration of the center of gravity of the population and GDP, and the areas with positive correlation between vegetation and terrestrial water reserves are mainly distributed in the northern slopes of the Kunlun Mountains, with an area proportion of about 50.513%. The Kumukuli Basin also shows significantly positive correlation.

Olive Mill Wastewaters Spreading on Agricultural Land: Results and Practical Management

Rich in water (88 to 95%), organic matter (6 to 14%) and mineral matter (1.5 to 4%), the olive mill wastewater or liquid effluent from the olive processing industry represents a certain fertilizer source. Four treatments (Control, 50, 100 and 200 m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; ha&amp;lt;sup&amp;gt;-1 &amp;lt;/sup&amp;gt;of OMWW) with an annual spreading of fresh OMWW, are applied to evaluate the effects of direct spreading of this by-product on the soil and the plant. From the first application, the level of organic matter changed significantly compared to the control soil without OMWW. In fact, three months after spreading, the respective levels of this substance increased from 0.42% in the control plot, to 0.91%, 1.02% and 1.47% respectively, for the spreading doses of 50, 100 or 200 m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. After several years, these same rates are only 0.84%, 0.91% and 0.95% for the respective doses of 50, 100 and 200 m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, indicating an intense activity of mineralization of organic matter under the effect of the soil microflora whose number has increased. The improvement in mineral status consequently improved the growth of olive groves with application doses of 50 and 100 m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. A decline in olive production was recorded with the dose 200 m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;, which could be explained by the inhibitory effect probably resulting from a slight toxic action of polyphenols accumulated in the soil. Finally, it should be noted that the results of this research led to the development of Decree No. 1308/2013 of February 26, 2013, authorizing the spreading of 50 m3 ha 1 of fresh vegetable water.

Modeling Nitrogen Fate and Water and Nitrogen Use Efficiencies under Different Greenhouse Vegetable Production Systems Using the WHCNS-Veg Model.

Quantitative evaluation of the effects of diverse greenhouse vegetable production systems (GVPS) on vegetable yield, soil water consumption, and nitrogen (N) fates could provide a scientific basis for identifying optimum water and fertilizer management practices for GVPS. This research was conducted from 2013 to 2015 in a greenhouse vegetable field in Quzhou County, North China. Three production systems were designed: conventional (CON), integrated (INT), and organic (ORG) systems. The WHCNS-Veg model was employed for simulating vegetable growth, water dynamics, and fates of N, as well as water and N use efficiencies (WUE and NUE) for four continuous growing seasons. The simulation results revealed that nitrate leaching and gaseous N emissions constituted the predominant N loss within GVPS, which separately accounted for 11.5-59.4% and 6.0-21.1% of the N outputs. The order of vegetable yield, N uptake, WUE, and NUE under different production systems was ORG > INT > CON, while the order of nitrate leaching and gaseous N loss was CON > INT > ORG. Compared to CON, ORG exhibited a significant increase in yield, N uptake, WUE, and NUE by 24.6%, 24.2%, 26.1%, and 89.7%, respectively, alongside notable reductions in nitrate leaching and gaseous N loss by 67.7% and 63.2%, respectively. The ORG system should be recommended to local farmers.

Using Geospatial Techniques to Analysis the Impact of Climate Change on Water and Agriculture Resources: Case study Khanaqin District in Diyala, Iraq

The study area was classified into three categories (vegetation cover, water, and others)using four satellite images of the Landsat 8 satellite captured during March for the period 2019-2022 into. The results showed that there is a change in the climatic conditions (temperature and rainfall) for the years of the study. The average temperature increased from 12.29°C to 25.967°C from the year 2019 to 2022. The annual amount of precipitation was decreased from 469.43 mm for the year 2019 to 105.49 mm for the year 2022.this negatively changed affected the water and agricultural resources, as the amount of water storage for Lake Hamrin and Lake Al-Wand together reached to 2,314,584,000 m3 and 40,404,000 m3 for the years 2019 and 2022, respectively. This led to decrease in the vegetation area from 1587.29 km2 to 356.17 for the year 2019 km2 and 2022, respectively.

Self Nanoemulsifying Solid of Atorvastatin Calcium – Development, Characterization and Evaluation

The aim of the present study is development and characterization of SNEDDS to enhance the bioavailability of anti-hyperlipidemic agent Atorvastatin calcium. The solubility was estimated in various solvent to find maximum solubility of drug in solvent. Vegetable oil (as vehicle), non-ionic surfactant (as surfactant, co-surfactant) and water is used to construct pseudo-ternary phase diagram (identify nanoemulsifying region). Stability, dispersibility and robustness to dilution to be performed for optimize formulations using phase diagram. Different formulations are prepared with various composition of vegetable oil, non-ionic surfactant. At one globule size of optimized system is expected to accept nano emulsion size range for improving the dissolution of Atorvastatin calcium. There by we may enhance the bio-availability of Atorvastatin.

Assessment of immediate and five-year earthquake impacts on river systems in sabah, Malaysia using multi-temporal satellite imageries

BackgroundEarthquake is one of the most destructive natural disasters, which cause immediate and long-term changes to the river systems. This research aimed to examine the immediate and five-year impacts of the 2015 Ranau Earthquake (6.0 Mw) on river systems in Malaysian state of Sabah, a region of low earthquake hazard.MethodsWe used object-based classification on Landsat 8 (2014 and 2015) and Sentinel-2A (2020) satellite imageries to derive land cover time series for investigating the impacts on the riparian areas.ResultsThe earthquake removed vegetation in the riparian zones of four rivers, the highest being the Penataran River (69.21 ha). During the immediate impact period (2014–2015), river bar formation occurred in all rivers, with the largest increase occurring in the Kadamaian River (56.97 ha), followed by the Panataran River (54.36 ha), which had no river bar before the earthquake. The river bar of the Kadamaian River continued to increase, whereas the river bar of the Panataran River decreased five years after the earthquake. Land cover transition analysis revealed that 78.39 ha of vegetation, barren land, and river water areas changed to river bars in the Kadamaian riparian area during the immediate impact period. Except for 26.87% of river bars in the Kadamaian riparian area in 2015, most river bars transitioned to other land cover types five years later. During the period of immediate impact, 22.05 ha of vegetation and 10.71 ha of river water were transformed into river bars along the Penataran River. Five years later, except for 16.2 ha, all river bar areas had transitioned to other cover types. Additionally, 17.7 ha of new river bars were formed. This study provides crucial data on post-earthquake land cover changes, particularly river bar formation and changes, for assessing the earthquake impacts on the river systems and supporting impact mitigation.

Study on Ecological Water Demand Pressure of Forest and Grass Vegetation Construction in Northwest Loess Plateau Based on Fitting Verification

In this paper, the minimum ecological water requirement of forest and grass vegetation in different types and regions and small basins in Pingliang City was analyzed and evaluated by using the quota of water consumption for ecological construction. The actual evapotranspiration water consumption of different types of vegetation was used as the quota to calculate the appropriate ecological water demand of vegetation, and the actual evapotranspiration water consumption of vegetation was used as the quota to calculate the appropriate ecological water consumption of vegetation in this region. At the same time, in order to make the calculation result more accurate, the water consumption per unit area after the actual evapotranspiration of different regions and different types of vegetation is used as the calculation quota. In addition, according to the principles of similar vegetation types, similar site conditions and similar climate environment, the research results of He Wentao et al., Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, on the ecological water requirement of forest in the whole Jinghe River basin (He Wentao et al. Determination and calculation of ecological water requirement of forest vegetation, Journal of Soil and Water Conservation, 2004, 18(6)) were selected and compared with this study. This study verifies the reliability of the calculation results of evapotranspiration water consumption of vegetation in this area. It should be noted that He Wentao et al. also evaluated the ecological water requirement of vegetation in the whole Jinghe River basin by calculating the evapotranspiration water consumption of vegetation, and analyzed the vegetation ecological water requirement deficit in 2020 by comparing the calculated minimum ecological water requirement of vegetation in the region, so as to reflect the ecological water demand pressure faced by vegetation construction in the region. It provides a basic basis for coordinating the relationship between vegetation construction and water resources in this region.

Evaluating the precise grapevine water stress detection using unmanned aerial vehicles and evapotranspiration-based metrics

AbstractPrecise irrigation management requires accurate knowledge of crop water demand to adequately optimize water use efficiency, especially relevant in arid and semi-arid regions. While unoccupied aerial vehicles (UAV) have shown great promise to improve the water management for crops such as vineyards, there still remains large uncertainties to accurately quantify vegetation water requirements, especially through physically-based methods. Notably, thermal remote sensing has been shown to be a promising tool to evaluate water stress at different scales, most commonly through the Crop Water Stress Index (CWSI). This work aimed to evaluate the potential of a UAV payload to estimate evapotranspiration (ET) and alternative ET-based crop water stress indices to better monitor and detect irrigation requirements in vineyards. As a case study, three irrigation treatments within a vineyard were implemented to impose weekly crop coefficient (Kc) of 0.2 (extreme deficit irrigation), 0.4 (typical deficit irrigation) and 0.8 (over-irrigated) of reference ET. Both the original Priestley-Taylor initialized two-source energy balance model (TSEB-PT) and the dual temperature TSEB (TSEB-2T), which takes advantage of high-resolution imagery to discriminate canopy and soil temperatures, were implemented to estimate ET. In a first step, both ET models were evaluated at the footprint level using an eddy covariance (EC) tower, with modelled fluxes comparing well against the EC measurements. Secondly, in-situ physiological measurements at vine level, such as stomatal conductance (gst), leaf (Ψleaf) and stem (Ψstem) water potential, were collected simultaneously to UAV overpasses as plant proxies of water stress. Different variants of the CWSI and alternative metrics that take advantage of the partitioned ET from TSEB, such as Crop Transpiration Stress Index (CTSI) and the Crop Stomatal Stress Index (CSSI), were also evaluated to test their statistical relationship against these in-situ physiological indicators using the Spearman correlation coefficient (ρ). Both TSEB-PT and TSEB-2T CWSI related similarly to in-situ measurements (Ψleaf: ρ ~ 0.4; Ψstem: ρ ~ 0.55). On the other hand, stress indicators using canopy fluxes (i.e. CTSI and CSSI) were much more effective when using TSEB-2 T (Ψleaf: ρ = 0.45; Ψstem: ρ = 0.62) compared to TSEB-PT (Ψleaf: ρ = 0.18; Ψstem: ρ = 0.49), revealing important differences in the ET partitioning between model variants. These results demonstrate the utility of physically-based models to estimate ET and partitioned canopy fluxes, which can enhance the detection of vine water stress and quantitatively assess vine water demand to better manage irrigation practices.

Research on Pattern Dynamics Behavior of a Fractional Vegetation-Water Model in Arid Flat Environment

In order to stop and reverse land degradation and curb the loss of biodiversity, the United Nations 2030 Agenda for Sustainable Development proposes to combat desertification. In this paper, a fractional vegetation–water model in an arid flat environment is studied. The pattern behavior of the fractional model is much more complex than that of the integer order. We study the stability and Turing instability of the system, as well as the Hopf bifurcation of fractional order α, and obtain the Turing region in the parameter space. According to the amplitude equation, different types of stationary mode discoveries can be obtained, including point patterns and strip patterns. Finally, the results of the numerical simulation and theoretical analysis are consistent. We find some novel fractal patterns of the fractional vegetation–water model in an arid flat environment. When the diffusion coefficient, d, changes and other parameters remain unchanged, the pattern structure changes from stripes to spots. When the fractional order parameter, β, changes, and other parameters remain unchanged, the pattern structure becomes more stable and is not easy to destroy. The research results can provide new ideas for the prevention and control of desertification vegetation patterns.

Investigating the regional ecological environment stability and its feedback effect on interference using a novel vegetation resilience assessment model

Vegetation resilience is critical for understanding the dynamic feedback effect of regional ecological environment stability against interferences. Thus, based on quantify the interferences of climate dryness and vegetation water deficit affecting vegetation growth function, incorporate mechanical Hooke's law to develop a vegetation resilience assessment model by quantitatively expressing vegetation growth function maintenance ability, to reveal the ecological environment stability and its feedback effect on interferences in the study area. The essential discoveries of the study are as follows: (1) with the increase of precipitation and the improvement of afforestation on soil erosion, the interferences intensity of climate dryness and vegetation water deficit in the ecological environment decreased by 5.88 % and 4.92 % respectively, the regional vegetation growth function loss was improved, especially in the southern region; (2) the decrease of vegetation growth function loss promoted the vegetation resilience level fluctuated from class II to class IV, with the average annual vegetation resilience increased by 7.02 %, reflecting that the regional ecological environment stability increased from difficult to rapid recovery after disturbance, and the benefit was especially noticeable in the eastern and southern forested areas; (3) the contribution rates of climate dryness and vegetation water deficit to the variation of vegetation resilience caused by vegetation restoration were −1.38 % and 4.73 %, respectively, and the prominent positive feedback effect of increasing vegetation resilience with decreasing vegetation water deficit degree in forest restoration area, indicating that the vegetation water deficit greatly impacts ecological environment stability in the study area, and forest restoration constantly improves regional ecological environment stability more than grassland restoration. This research has crucial guiding implications for supporting the sustainable development of regional ecological environments.

An Investigation of the Impact of Spatiotemporal Changes of Land Use and Land Cover and Land Surface Temperature Using RS Techniques for Selected Cities in Sri Lanka

Changes in land use and land cover (LULC) have an impact on land surface temperature (LST) locally, regionally, and globally. This research focused on the spatiotemporal dynamics of LULC and LST between 2000 and 2021 at six selected meteorological stations, belonging to the different climatic zones of Sri Lanka. The LULC were classified from Landsat ETM+ and OLI/TIRS data using the maximum likelihood classification approach, while LST was retrieved using the thermal band of both Landsat images. Resultsreveal that the built-up areas have increased in all selected locations and bare land, vegetation cover, and agricultural land have all declined in the last 20 years. In Galle and Batticaloa areas, built-up areas have grown significantly by 11.9% and 11.14% respectively, by 2021. The thermal environment spatiotemporal alterations were consistent with the urbanization trend. Since many other land use types have been converted into urban areas, the average LST in Vavuniya, Anuradhapura, Batticaloa, and Galle has been rising steadily. This showed that increasing built-up area density has played a significant role in raising LST in the study areas. The vegetation cover, agricultural land, and water bodies showed the least LST change. By examining the correlation analysis between the Normalized Difference Vegetation Index (NDVI) and LST, a somewhat positive relationship was revealed only in the areas of Galle, Batticaloa, and Hambantota. Nevertheless, the findings of this study will serve as a helpful benchmark for future landscape and urban design initiatives aimed at reducing the detrimental effects of LST on urban sustainability.

Wheat height and phenology retrieval using GPS/BDS interferometric reflectometry technology

Monitoring vegetation growth utilizing the Global Navigation Satellite System-interferometric reflectometry (GNSS-IR) technology has obtained widespread attention in recent years. GNSS-IR based approaches demonstrate the advantageous characteristics of high temporal resolution while maintaining cost-effectiveness. Most existing studies generally utilize reflected signals to retrieve the plant height and vegetation water content, while few studies focus on vegetation phenology and yield. In this study, both phenology metric dates and plant height of wheat were extracted using reflected signals data from GPS and BeiDou Navigation Satellite System (BDS) in a wheat farmland, located at northeast of Henan, China. The results showed that there was reasonable consistency between the retrieval heights and in-situ measurements, with the correlation coefficient of 0.836 for GPS and 0.868 for BDS. The damping coefficient calculated by signal-to-noise ratio (SNR) presented obvious characteristics during different wheat growth stages and the trends of the damping coefficient were basically consistent with that of the normalized difference vegetation index (NDVI). When taking a lag between the leaf area index (LAI) and the damping coefficient into consideration, the correlation was greatly increased. Moreover, the phenology metrics dates extracted by the damping coefficient were close to those estimated by NDVI with errors less than 8 days. Hence, this research preliminarily proves the feasibility of obtaining the wheat phenological period by using GNSS-IR technology.

Mechanistically derived macroscopic root water uptake functions: The α and ω of root water uptake functions

AbstractWater uptake by plant roots is an important component of the soil water balance. Predicting to what extent potential transpiration from the canopy, that is, transpiration demand, can be met by supply of water from the soil through the root system is crucial to simulate the actual transpiration and assess vegetation water stress. In models that simulate the dynamics of vertical soil water content profiles as a function of water fluxes and soil water potential gradients, the root water uptake (RWU) distribution is represented by macroscopic sink terms. We present RWU functions that calculate sink terms based on a mechanistic model of water flow in the soil–root system. Based on soil–root hydraulics, we define α‐supply functions representing the maximal uptake by the root system from a certain soil depth when the root collar water potential equals the wilting point, ω‐supply factors representing the maximal supply from the entire root system, and a critical ωc factor representing the potential transpiration demand. These functions and factors are subsequently used to calculate RWU distributions directly from potential transpiration or demand and the soil water potentials. Unlike currently used approaches, which define α‐stress functions and ω factors representing ratios of actual uptake to uptake demand, the supply‐based formulations can be derived directly from soil and root hydraulic properties and can represent processes like root hydraulic redistribution and hydraulic lift.

Developing simple indicators of nitrogen and phosphorus removal in constructed stormwater wetlands

Quantifying pollutant removal by stormwater wetlands requires intensive sampling which is cost-prohibitive for authorities responsible for a large number of wetlands. Wetland managers require simple indicators that provide a practical means of estimating performance and prioritising maintenance works across their asset base. We therefore aimed to develop vegetation cover and metrics derived from monitoring water level, as simple indicators of likely nutrient pollutant removal from stormwater wetlands. Over a two-year period, we measured vegetation cover and water levels at 17 wetlands and used both to predict nitrogen (N) and phosphorus (P) removal. Vegetation cover explained 48 % of variation in total nitrogen (TN) removal; with a linear relationship suggesting an approximate 9 % loss in TN removal per 10 % decrease in vegetation cover. Vegetation cover is therefore a useful indicator of TN removal. Further development of remotely-sensed data on vegetation configuration, species and condition will likely improve the accuracy of TN removal estimates. Total phosphorus (TP) removal was not predicted by vegetation cover, but was weakly related to the median water level which explained 25 % of variation TP removal. Despite weak prediction of TP removal, metrics derived from water level sensors identified faults such as excessive inflow and inefficient outflow, which in combination explained 50 % of the variation in the median water level. Monitoring water levels therefore has the potential to detect faults prior to loss of vegetation cover and therefore TN removal, as well as inform the corrective action required.

Vegetation–Topographic Landscape and the Influence of Water and Sediment in the Shule River Basin

The study of the effect of vegetation cover on water and sediment content is of great significance for the in-depth understanding of ecological and environmental effects in river basins and the formulation of corresponding management measures. Based on the monitoring data of rainfall and runoff of Panjiazhuang and Dangchengwan Hydrologic Stations in Shule River Basin from 2000 to 2020 and the sediment discharge of Changmabao, methods such as geographic information technology (GIS), landscape pattern analysis, land use transfer matrix, correlation analysis, principal component analysis, and linear regression analysis were used to study water and sediment change, land use pattern, vegetation change characteristics, and local water and sediment change in Shule River Basin and construct vegetation–topographic landscape factors. The main research results are as follows: (1) Vegetation coverage in the Shule River Basin increased year by year from 2000 to 2020, with a cumulative increase of 0.064 in 20 years. Vegetation cover has a significant effect on water and sediment content, and the correlation is −0.966. (2) The cultivated land area of the Shule River Basin increased by 604 km2 from 2000 to 2020, and the conversion rate was 67%. From 2000 to 2020, the water area increased by 442 km2, and the conversion rate was 51%. The area of grassland and forest increased by 198 km2 and 12 km2, respectively, and the conversion rate was 68% and 33%, respectively. Forest had the highest transfer rate (0.67). The lowest conversion rate was 0.32 for grassland. (3) The variation coefficient of water and sediment content in Shule River Basin during 1971–2020 was 45.21%, and the highest variation coefficient during 2001–2010 was 49.15%. The lowest variation coefficient was 39.73% during 2011–2020. The annual sediment transport in the Shule River Basin fluctuates greatly and has a high degree of dispersion during 1971–2020. (4) The results of the landscape index in Shule River Basin during 2000–2020 had a small difference, with a difference of less than 0.5. According to the principal component analysis of landscape index and water and sediment content, the maximum patch index (LPI) had the strongest positive correlation with water and sediment content (0.958). The diversity index SHDI had the strongest negative correlation with water and sediment content (−0.995).

Spatiotemporal coverage capability of moon-based SAR for water dynamic monitoring in global vegetation tipping elements

ABSTRACT Changes in water content dynamics can serve as predictive indicators for catastrophic transitions in vegetation tipping elements. Vegetation water content is a rapidly changing parameter with sub-daily fluctuations, and current space-borne sensors fall short of providing adequate spatiotemporal coverage for effective analysis. The Moon-based Earth observation, i.e. Synthetic Aperture Radar has recently showcased prolonged durations, rapid revisiting rates, and extensive monitoring capabilities with a decent spatial resolution (10-100 m). This opens up new possibilities for vegetation water content monitoring which has not yet been discussed. The study has assessed its monitoring capability in four critical vegetation tipping elements and considered both overall temporal observation availability fraction and diurnal variation acquisition. The results indicate that Amazon and Sahelian regions can be observed for ∼30% of a nutation period (∼18.6 years). Diurnal variations in water content can be captured with a 1-hour interval every 16–23 days for the Amazon and Sahelian regions. For polar tundra and boreal regions, continuous observation spanning 7–12 h can be achieved. These outstanding characteristics offer a deeper understanding of water content dynamics in vegetation tipping elements, which will enhance our prediction for their critical transitions.

Development of a new rotational irrigation model in an arid basin based on ecological zoning and sluice regulation

Precise and efficient allocation of existing water resources is of great significance to protect and restore desert riparian forests in inland river basins. However, the lack of detailed ecological zoning in most basins hinders the optimization of the current ecological sluice regulation scheme, leading to low effectiveness in vegetation restoration and water resources management. To address this problem, we proposed for the first time an ecological zoning method that integrates the vegetation gradient model and control of ecological sluices. Specifically, the mainstream of Tarim River basin (China) was classified into three types of ecological functional zones, i.e., key protection, key restoration, and ecologically sensitive zones, based on the kernel NDVI (kNDVI) gradient detection framework. On this basis, the basin was divided into 27 sluice group control areas determined by the control range of ecological sluices and the study area was further divided into five grades zones of ecological rotation irrigation. Based on the results of ecological zoning and the priorities of rotational irrigation, this study proposes a new rotational irrigation model in the basin to further promote vegetation recovery. The results showed that guarantee rate of ecological water supply to vegetation protection and restoration increased from 82.3% to 101.7% before and after rotational irrigation, respectively, indicating the effectiveness of this new method. The results of this study have a practical value and may significantly contribute to the optimal allocation and management of water resources in global arid basins.

Indigenous lands and conservation units slow down non-GHG climate change in the Cerrado-Amazon ecotone

Preserving tropical forests by avoiding deforestation and forest degradation is essential for maintaining ecosystem services. Brazilian Conservation Units (CUs) and Indigenous Lands (ILs) have effectively prevented deforestation and supported climate regulation. However, these protected areas face increasing threats from forest fires and droughts across the Amazon and Cerrado biomes. This study assesses how disturbances affect climate regulating factors (surface temperature (LST), evapotranspiration (ET), and albedo) in Mato Grosso state, among different land uses (CUs, ILs, and multiple-use areas - MUs). To do so, we analyzed satellite data collected between 2001 and 2020. Results showed that MUs (outside protected areas) had lower ET (∼10%), higher daytime LST (∼1.5 °C), and higher albedo (∼10%) than CUs and ILs in both biomes in 2001. Over the study period, MUs experienced a greater increase in LST (Amazon: ∼1.4 °C; Cerrado: ∼1.1 °C) and albedo (Amazon: ∼6%; Cerrado: ∼3%) compared to protected areas, regardless of the biome. In contrast, ILs and CUs showed smaller mean changes in LST (∼0.2 °C), ET (∼1.3%), and albedo (∼1.3%). These changes were associated with native vegetation loss, forest fires, and water stress. Our results highlight the important role of protected areas in maintaining climate stability, with higher ET, lower LST, and lower albedo than other land uses. However, the long-term preservation of these services within protected areas depends on interventions in surrounding regions, particularly in the Amazon. Protecting and restoring these natural ecosystems is key for safeguarding ecosystem services and climate regulation in tropical regions.