Hydrometeorological Changes Research Articles

Response to hydrometeorological changes and evaluation of habitat quality in the Dongting Lake basin, China

ABSTRACT With the advancement of hydraulic engineering processes, surface water resources are encountering unprecedented crises that threaten social and ecological sustainability. This study analyzed the response changes and potential correlations between river conditions and climate change in the Dongting Lake (DTL) basin using gray correlation analysis and the LSTM model. Additionally, the InVEST model was employed to further assess the distribution of habitat quality within the basin. The results of the study showed that (1) the range of variation of environmental flows in each tributary became significantly narrower and the frequency of extreme hydrological conditions was reduced in the period after the abrupt hydrological change. (2) The hydrological status had a higher degree of correlation with the rainfall index, and the performance is more prominent on the Xiang River, and the influence of temperature is less. (3) Except in the Xiang River Basin, human activities are the dominant factor of runoff variation, and the annual contribution is generally higher than 50%. (4) Habitat quality in the ‘high’ distribution was the most guarded and always accounted for more than 60% of the basin, while habitat quality in the east-central part of the DTL basin and around the DTL was generally low.

Multi-decadal floodplain classification and trend analysis in the Upper Columbia River valley, British Columbia

Abstract. Floodplain wetland ecosystems experience significant seasonal water fluctuation over the year, resulting in a dynamic hydroperiod, with a range of vegetation community responses. This paper assesses trends and changes in land cover and hydroclimatological variables, including air temperature, river discharge, and water level in the Upper Columbia River Wetlands (UCRW), British Columbia, Canada. A land cover classification time series from 1984 to 2022 was generated from the Landsat image archive using a random forest algorithm. Peak river flow timing, duration, and anomalies were examined to evaluate temporal coincidence with observed land cover trends. The land cover classifier used to segment changes in wetland area and open water performed well (kappa of 0.82). Over the last 4 decades, observed river discharge and air temperature have increased, precipitation has decreased, the timing of peak flow is earlier, and the flow duration has been reduced. The frequency of both high-discharge events and dry years have increased, indicating a shift towards more extreme floodplain flow behavior. These hydrometeorological changes are associated with a shift in the timing of snowmelt, from April to mid-May, and with seasonal changes in the vegetative communities over the 39-year period. Thus, woody shrubs (+6 % to +12 %) have expanded as they gradually replaced marsh and wet-meadow land covers with a reduction in open-water area. This suggests that increasing temperatures have already impacted the regional hydrology, wetland hydroperiod, and floodplain land cover in the Upper Columbia River valley. Overall, there is substantial variation in seasonal and annual land cover, reflecting the dynamic nature of floodplain wetlands, but the results show that the wetlands are drying out with increasing areas of woody/shrub habitat and loss of aquatic habitat. The results suggest that floodplain wetlands, particularly marsh and open-water habitats, are vulnerable to climatic and hydrological changes that could further reduce their areal extent in the future.

Elevational Patterns of Forest Evapotranspiration and Its Sensitivity to Climatic Variation in Dryland Mountains

Elevational climatic heterogeneity, complex terrains, and varying subsurface properties affect the sensitivity of evapotranspiration (ET) in dryland mountain forests to hydrometeorological changes. However, the elevational distribution of ET sensitivity and its major influencing factors remain poorly understood. This study focused on the mid-altitude zone (1000–3500 m) forests in the Chinese Western Tianshan Mountains and assessed ET sensitivity to multiple climate variables, including precipitation (P) and potential evapotranspiration (PET), from 2000 to 2020. To evaluate the multi-year mean and trends in ET sensitivity, multi-source remote sensing data and regional survey data were analyzed using Spearman’s correlation coefficient, the sliding window method, and Kendall’s test. Furthermore, the relative importance of environmental variables (topography, geology, soil, and vegetation) was investigated. P and PET showed no significant trends, while ET exhibited a significant increasing trend (5.81 mm/yr, p < 0.01), particularly at elevations above 2000 m. Most forests (93.5%) showed a positive sensitivity of ET to P, and 70.0% showed a positive sensitivity of ET to PET, mainly at elevations of 1500–2500 m. Additionally, the trend in ET sensitivity to P decreased with an increasing elevation, with 64.5% showing a positive trend. Meanwhile, the trend in ET sensitivity to PET increased with elevation, with 88.1% showing a positive trend. Notably, 53.2% of the forests showed increasing ET sensitivity trends to both P and PET, primarily at elevations of 2000–3000 m with a mean normalized difference vegetation index (NDVI) of 0.56. Geological factors, particularly the hydrological properties of weathered bedrock, contributed the most (~47%) to mean sensitivity. However, geological and vegetative factors, including the NDVI and root zone water availability, were the main contributors (35% each) to the sensitivity. This study highlights the elevation-dependent sensitivity of dryland mountain forests to hydrothermal changes, with higher-elevation forests (>2000 m) being more sensitive to global warming.

Forecast of Hydro–Meteorological Changes in Southern Baltic Sea

Forecast of Hydro–Meteorological Changes in Southern Baltic Sea

Engineering Approach to Assessing the Vulnerability of Water Abstraction

Variability in stream flow/discharge results in serious problems for engineers and difficulties in characterizing water systems under future climatic conditions. The management of water security in the engineering domain requires approaches aimed at minimizing the detrimental effects of the hydrological behavior of natural systems. Abstraction facilities must be strengthened to ensure sustainable supply and water security over time and at different scales. Several approaches and methodologies have been developed to translate water security into a framework that provides information on how to improve it. In this study, a scalar range idea is used to evaluate the sensitivity of a water resource system and cause–effect linkages define the vulnerability indicator as management-relevant information to address water security. This intuitively relates the extreme deviations of a particular streamflow to the average system response related to a particular hazard indicator. This determines the current stress in the operation of the abstraction facilities based on historical hydrometeorological changes, which is the basis for assessing future operational conditions and risks. This study uses streamflow extremes and averages as hazard-relevant indicators of water supply security. The results of the two case studies show that the applied approach fully appreciates the internal properties of water resource systems that affect the sensitivity/vulnerability of streamflow, as well as the derived streamflow vulnerability index and function. The obtained results were used to assess the vulnerability of water intake as well as the choice of safety factors and design parameters in accordance with the forecasted average annual and seasonal climate factors.

Recent Changes in Hydrometeorological Extremes in the Bilate River Basin of Rift Valley, Ethiopia

The hydroclimatic extremes such as floods and droughts have been causing damage and losses with rising frequency than ever before. The human-induced and internal climate variability create extreme events and local hydrometeorological changes influencing climate-sensitive sectors. This research is aimed at analyzing the recent changes in the hydrometeorological extremes using indices over the Bilate basin in Ethiopia. Mann-Kendall and Sen’s slope estimator were used to examine changes in hydrometeorological extreme indices. The rainy days’ rate of change falls between +10.64 mm in the downstream to −10.67 mm in the upstream north. The wet day rainfall and heavy rainfall day indices were stronger in the basin’s southwest, implying more likely flood events. The consecutive dry days show a rising tendency with more variability, while the consecutive wet days show no trend with less variability. The change point analysis revealed inconsistencies for the majority of the extreme indices. The stations’ average warmest nights and days significantly increased at a rate of 0.0358°C and 0.0320°C per annum, respectively. The coldest nights in most of the stations show a significant and negligible rise in the basin while on the coldest days more than half of the stations declining. The peak flow in the annual and seasonal time series shows a rising trend and a dominant rise in most low flow indices, which possibly flashes downstream flooding. The global and local climate anomalies revealed a weak correlation, but with overlap of wet and drought years. Basin water resource plans may benefit from identified overlap cross of threshold years for improved flood control and drought monitoring.

Projecting future risk of dengue related to hydrometeorological conditions in mainland China under climate change scenarios: a modelling study

We have limited knowledge on the impact of hydrometeorological conditions on dengue incidence in China and its associated disease burden in a future with a changed climate. This study projects the excess risk of dengue caused by climate change-induced hydrometeorological conditions across mainland China. In this modelling study, the historical association between the Palmer drought severity index (PDSI) and dengue was estimated with a spatiotemporal Bayesian hierarchical model from 70 cities. The association combined with the dengue-transmission biological model was used to project the annual excess risk of dengue related to PDSI by 2100 across mainland China, under three representative concentration pathways ([RCP] 2·6, RCP 4·5, and RCP 8·5). 93 101 dengue cases were reported between 2013 and 2019 in mainland China. Dry and wet conditions within 3 months lag were associated with increased risk of dengue. Locations with potential dengue risk in China will expand in the future. The hydrometeorological changes are projected to substantially affect the risk of dengue in regions with mid-to-low latitudes, especially the coastal areas under high emission scenarios. By 2100, the annual average increased excess risk is expected to range from 12·56% (95% empirical CI 9·54-22·24) in northwest China to 173·62% (153·15-254·82) in south China under the highest emission scenario. Hydrometeorological conditions are predicted to increase the risk of dengue in the future in the south, east, and central areas of mainland China in disproportionate patterns. Our findings have implications for the preparation of public health interventions to minimise the health hazards of non-optimal hydrometeorological conditions in a context of climate change. National Natural Science Foundation of China.

Projecting future risk of dengue related to hydrometeorological conditions in mainland China under climate change scenarios

BACKGROUND AND AIM Limited knowledge is known about the impact of hydrometeorological conditions on dengue incidence in China, and the associated disease burden in the climate-changing future. This study projects the attributable excess risk of dengue in 365 cities across mainland China under climate change scenarios. METHODS The association between Palmer drought severity index (PDSI) and dengue in the historical period (2013-2019) was estimated with a spatiotemporal Bayesian model. We developed a dengue transmission biological model to project the potential risk area of dengue by 2100 under three representative concentration pathways (RCP 2.6, 4.5, and 8.5). The association combined with biological model was then used to project the annual excess risks of dengue related to PDSI by 2100. We further calculated attributable excess risk for dry and wet conditions. RESULTS A total of 93,101 dengue cases were reported between 2013-2019 in mainland China. Dry and wet conditions within three months lag were associated with increased risk of dengue. Locations with potential dengue risk in China will expand in the future. The hydrometeorological changes are projected to substantially affect the risk of dengue in regions with mid-low latitude, especially the coastal areas under high emission scenarios. By 2100, the annual average increased excess risk is expected to range from 7.49% (95% empirical CI: 4.55-16.64) in northwest to 71.89% (55.66-123.62) in south under RCP 8.5. Moderate dry is predicted to have the greatest impact on dengue risk across all regions. CONCLUSIONS Hydrometeorological conditions are predicted to increase the dengue risk in the future in the south, east, and central areas of mainland China in disproportional patterns. Our findings have implications for the preparation of public health interventions to minimize the health hazards of non-optimal hydrometeorological conditions under climate change context. KEYWORDS Climate change; Dengue; Hydrometeorology; Palmer drought severity index

A new multi-variable integrated framework for identifying flash drought in the Loess Plateau and Qinling Mountains regions of China

Flash drought is an extreme phenomenon, characterized by unusually rapid intensification of drought severity, with strong impacts on plant growth especially for crops. However, it’s unclear how hydrometeorological changes contribute to flash drought and how vegetation physiology, greenness, and productivity respond to flash drought. In this study, we developed an multivariate integrated framework for flash drought identification using a regression model based on principal-components analysis (PCA): the PCA regression flash drought (PRFD) model. Three criteria are specified to emphasize the rapid intensification of drought and its impacts on vegetation growth and water resources. We applied our new model in two geographical units with different climates and hydrology: one is dominated by agriculture and subject to natural drought (the Loess Plateau) and the other, a natural region with infrequent drought (the Qinling Mountains). We found that high frequency of flash droughts is most likely to occur in the eastern and central Loess Plateau and part of the Qinling Mountains. However, in relatively humid areas, flash drought shows strong intensity such as the Qinling Mountains and western and eastern edges of the Loess Plateau. Trend analysis indicates that PRFD has increased frequency, longer duration, and stronger intensity since the 1990s in both regions. From an ecological perspective, PRFD also showed a spatial pattern consistent with values of vegetation-related proxies that were below the long-term average, demonstrating vegetation transpiration, normalized-difference vegetation index (NDVI), gross primary productivity have obvious feedback on flash drought events. The Loess Plateau’s NDVI responded immediately to flash drought, versus a 1-month lag in the Qinling Mountains. Because our proposed framework integrates multiple aspects of drought information, it can be applied in areas outside the study region according to regional hydrometeorological conditions. This has significant implications for improving agricultural management and forecasting future severe impacts of flash drought on plant growth.

Delayed subsidence of the Dead Sea shore due to hydro-meteorological changes

Many studies show the sensitivity of our environment to manmade changes, especially the anthropogenic impact on atmospheric and hydrological processes. The effect on Solid Earth processes such as subsidence is less straightforward. Subsidence is usually slow and relates to the interplay of complex hydro-mechanical processes, thus making relations to atmospheric changes difficult to observe. In the Dead Sea (DS) region, however, climatic forcing is strong and over-use of fresh water is massive. An observation period of 3 years was thus sufficient to link the high evaporation (97 cm/year) and the subsequent drop of the Dead Sea lake level (− 110 cm/year), with high subsidence rates of the Earth’s surface (− 15 cm/year). Applying innovative Global Navigation Satellite System (GNSS) techniques, we are able to resolve this subsidence of the “Solid Earth” even on a monthly basis and show that it behaves synchronous to atmospheric and hydrological changes with a time lag of two months. We show that the amplitude and fluctuation period of ground deformation is related to poro-elastic hydro-mechanical soil response to lake level changes. This provides, to our knowledge, a first direct link between shore subsidence, lake-level drop and evaporation.

The long-term ichthyoplankton abundance summer trends in the coastal waters of the Black Sea under conditions of hydrometeorological changes

In this study a long-term literature and field-monitoring dataset collected from the Sevastopol coast in the Black Sea during summer seasons from 1960 to 2017 were examined. Principal component analysis (PCA) and ANOVA analysis clearly demonstrate changes in the dynamics of ichthyoplankton abundance due to wind conditions, temperature, and salinity. The results specifically showed significant relationship between the abundance of eggs (r = 0.82) and repeatability northeasterly winds and between larvae abundance and speed northeasterly wind (r = 0.64). As the wind speed increases, the surface water temperature decreases and salinity rises. According to the data on the temperature and wind speed, the period of occurrence of local upwellings in summer near the coast of Sevastopol was determined ~8 and 20–25 years. Based on analysis of linear trends for the summer periods from 1960 to 2017 in this area a decrease in the number of fish eggs and occurrences of larvae and a general reduction in temperatures, salinity, speed and repeatability northeasterly winds was observed. Long-term ichthyoplankton data monitoring can be used to validate model results and provide further predictions of changes in ecosystem components.

Impending Hydrological Regime of Lhasa River as Subjected to Hydraulic Interventions—A SWAT Model Manifestation

The damming of rivers has altered their hydrological regimes. The current study evaluated the impacts of major hydrological interventions of the Zhikong and Pangduo hydropower dams on the Lhasa River, which was exposed in the form of break and change points during the double-mass curve analysis. The coefficient of variability (CV) for the hydro-meteorological variables revealed an enhanced climate change phenomena in the Lhasa River Basin (LRB), where the Lhasa River (LR) discharge varied at a stupendous magnitude from 2000 to 2016. The Mann–Kendall trend and Sen’s slope estimator supported aggravated hydro-meteorological changes in LRB, as the rainfall and LR discharge were found to have been significantly decreasing while temperature was increasing from 2000 to 2016. The Sen’s slope had a largest decrease for LR discharge in relation to the rainfall and temperature, revealing that along with climatic phenomena, additional phenomena are controlling the hydrological regime of the LR. Reservoir functioning in the LR is altering the LR discharge. The Soil and Water Assessment Tool (SWAT) modeling of LR discharge under the reservoir’s influence performed well in terms of coefficient of determination (R2), Nash–Sutcliffe coefficient (NSE), and percent bias (PBIAS). Thus, simulation-based LR discharge could substitute observed LR discharge to help with hydrological data scarcity stress in the LRB. The simulated–observed approach was used to predict future LR discharge for the time span of 2017–2025 using a seasonal AutoRegressive Integrated Moving Average (ARIMA) model. The predicted simulation-based and observation-based discharge were closely correlated and found to decrease from 2017 to 2025. This calls for an efficient water resource planning and management policy for the area. The findings of this study can be applied in similar catchments.

Potential Associations between Low-Level Jets and Intraseasonal and Semi-Diurnal Variations in Coastal Chlorophyll—A over the Beibuwan Gulf, South China Sea

Low-level jet (LLJ) significantly affects the synoptic-scale hydrometeorological conditions in the South China Sea, although the impact of LLJs on the marine ecological environment is still unclear. We used multi-satellite observation data and meteorological reanalysis datasets to study the potential impact of LLJs on the marine biophysical environment over the Beibuwan Gulf (BBG) in summer during 2015–2019. In terms of the summer average, the sea surface wind vectors on LLJ days became stronger in the southwesterly direction relative to those on non-LLJ days, resulting in enhanced Ekman pumping (the maximum upwelling exceeds 10 × 10−6 m s−1) in most areas of the BBG, accompanied by stronger photosynthetically active radiation (increased by about 20 μmol m−2 s−1) and less precipitation (decreased by about 3 mm day−1). These LLJ-induced hydrometeorological changes led to an increase of about 0.3 °C in the nearshore sea surface temperature and an increase of 0.1–0.5 mg m−3 (decrease of 0.1–0.3 mg m−3) in the chlorophyll-a (chl-a) concentrations in nearshore (offshore) regions. Intraseasonal and diurnal changes in the incidence and intensity of LLJs potentially resulted in changes in the biophysical ocean environment in nearshore regions on intraseasonal and semi-diurnal timescales. The semi-diurnal peak and amplitude of chl-a concentrations on LLJ days increased with respect to those on non-LLJ days. Relative to the southern BBG, LLJ events exhibit greater impacts on the northern BBG, causing increases of the semi-diurnal peak and amplitude with 1.5 mg m−3 and 0.7 mg m−3, respectively. This work provides scientific evidence for understanding the potential mechanism of synoptic-scale changes in the marine ecological environment in marginal seas with frequent LLJ days.

Water Blooming in the Reservoir with Long-Term Discharge Regulation

The factors of phytoplankton development in the stratified Mozhaisk Reservoir are analyzed on the basis of long-term observations and model calculations. To analyze the variability of phytoplankton biomass values, the weather contrast index based on the identification of synoptic cycles of water surface temperature was used. A comparative assessment of the water blooming intensity in different years was carried out based on the water blooming index, calculated as the sum of the daily values of phytoplankton biomass resulted from the model calculations. The study analyzes specific features of the development of diatoms and cyanobacteria in the reservoir depending on hydro-meteorological conditions and long-term changes in the values of water blooming and weather contrast indices.

ANALYSIS OF LONG-TERM VARIABILITY OF RIVER RUNOFF IN THE URAL RIVER BASIN

The hydrological zoning of the Ural River basin has been clarified in terms of synchronism and in-phase fluctuations in annual runoff. 5 hydrological regions have been identified. For 9 hydrological posts and 5 meteorological stations located in different parts of the basin, a detailed statistical analysis of long-term data was carried out. A single 1975 year of the beginning of hydro-meteorological changes in the basin was revealed. For each hydrological region, statistically significant changes in the annual and seasonal runoff were revealed. The assessment of the factors of change in runoff was carried out. Areas with a predominant influence on the change in runoff or anthropogenic load on water resources or climatic changes are identified.

Design of Ship Navigation Trajectory Analysis and Application System Based on Image Processing Technology

Wei, Y., 2020. Design of ship navigation trajectory analysis and application system based on image processing technology. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 211-213. Coconut Creek (Florida), ISSN 0749-0208.In recent years, maritime trade has been developing continuously, the density of ships in ports and maritime routes has been increasing, and maritime traffic accidents have occurred frequently. With the development of economic globalization, more and more frequent commodity trade has appeared between countries in the world. Maritime container transportation has higher safety, lower cost and relatively large actual transportation volume. Maritime navigation is characterized by dynamic and non-repeatable positioning and navigation compared with land due to fuzzy route boundaries, frequent hydrometeorological changes, dynamic and changeable water depth and the influence of obstacles. In the process of the development of maritime trade, a great deal of energy should be devoted to the technical research work of ship navigation in the sea area and the analysis of ship's navigation trajectory. In this paper, the analysis of ship's trajectory is taken as the analysis object, and the analysis and prediction are carried out on the basis of image processing, so that the incidence of maritime traffic accidents can be reduced.

The heterogeneity of hydrometeorological changes during the period of 1961-2016 in the source region of the Yellow River, China

The heterogeneity of hydrometeorological changes during the period of 1961-2016 in the source region of the Yellow River, China

Hydrometeorological changes in the North-East of Russia

The paper presents a comprehensive analysis of hydrometeorological changes at the river basins of the North-East of Russia for the period 1966-2015. Data from 61 meteorological stations showed an increase in the air temperature by an average of 2.3 °C and multidirectional changes in annual precipitation. Most stations are characterized by a significant negative trend of precipitation in winter and a positive annual trend of mixed and liquid precipitation with an increase in their share in autumn months. The presence of statistically significant positive streamflow trends in the autumn-winter period was established for 51 hydrological gauges. We hypothesize that the increase in the low flow is mainly due to the transition of precipitation type from solid to liquid and corresponding increase of runoff in September, continuing in the following months.

Tracking Montane Mediterranean grasslands: Analysis of the effects of snow with other related hydro-meteorological variables and land-use change on pollen emissions

This paper explores the dynamics of temporal evolution of the high mountain Mediterranean grasslands, (Sierra Nevada, Spain SE). The indicator used is the emission of pollen (Pollen Index, PI) with respect to two important aspects: the incidence of the snow dynamic together with other hydro-meteorological parameters, and the changes in land use, which can Influence the evolution of the grasslands throughout time. The results reveal that pollen emissions in the last 25 years have shown a slight downward trend, with large interannual fluctuations, which are a consequence of diverse environmental factors, both general and specific to the area. One of the most influential parameters on pollen concentrations is snow cover, which reinforces the importance of the presence of snow-packs as water resource outside the winter season in the High Mediterranean Mountain environments. The changes in land use experienced in the area are a driver of change, especially due to the losses experienced in the last decades in the preferred habitats for many species of grasses. It can be concluded that the vulnerability of these ecosystems will be affected by an increase in winter temperatures and/or a decrease in rainfall (climate change) and an increase in the intensity of anthropogenic activities on land use. In this context, the PI is shown as a useful indicator of global change given its sensitivity to both anthropic and hydro-meteorological changes. In addition, it has a wide range of spatial detection and discrimination capacity by altitudinal dimensions.

Investigation of the Behavior of an Agricultural-Operated Dam Reservoir Under RCP Scenarios of AR5-IPCC

In regions where the Mediterranean climate prevails, the agricultural sector and agricultural-operated dam reservoirs are threatened by climate change. In this respect, the prediction of hydro-meteorological changes that may occur in surface water resources under climate change scenarios is essential to examine the sustainability of reservoirs. In this paper, Demirkopru reservoir in the Gediz Basin/Turkey, a reservoir operated for irrigation purposes, was analyzed against the RCP4.5 and RCP 8.5 scenarios specified in the AR5 report of the IPCC. Projection period was evaluated as 2016-2050 water year period. First, statistical downscaling, Bayesian model averaging and quantile delta mapping bias correction techniques were respectively applied to monthly total precipitation and monthly average temperatures of meteorological stations in the region using 12 GCMs. According to RCP4.5 and RCP8.5, negligible reductions in precipitation are foreseen, while significant increases of 1.3 and 1.8 °C, respectively, are projected for temperatures under the same scenarios. Following the calibration of rainfall-runoff models for the sub-basins feeding the reservoir, streamflow simulations were also performed with projected precipitation and temperatures. In particular, according to the RCP 8.5 scenario, reservoir inflows during the period 2016-2050 could be reduced by 21% compared to the reference scenario results. Finally, the projected crop water demands and hydro-meteorological changes are evaluated together and the reservoir performances are examined using various indices. Assuming that the performance of the past irrigation yields will not change in the future, it is foreseen that reservoir’s sustainability will decrease by 16% under the RCP8.5 scenario. Even if the irrigation efficiency is increased by 40%, the reservoir cannot reach past sustainability characteristics.