We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958-2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from other sources to produce a monthly dataset of precipitation, maximum and minimum temperature, wind speed, vapor pressure, and solar radiation. TerraClimate additionally produces monthly surface water balance datasets using a water balance model that incorporates reference evapotranspiration, precipitation, temperature, and interpolated plant extractable soil water capacity. These data provide important inputs for ecological and hydrological studies at global scales that require high spatial resolution and time varying climate and climatic water balance data. We validated spatiotemporal aspects of TerraClimate using annual temperature, precipitation, and calculated reference evapotranspiration from station data, as well as annual runoff from streamflow gauges. TerraClimate datasets showed noted improvement in overall mean absolute error and increased spatial realism relative to coarser resolution gridded datasets.

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TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958-2015.

Foreword 1. Introduction 2. Runoff, erosion and delivery to the coastal ocean 3. Temporal variations 4. Human impacts Appendices. Global River Database: Appendix A: North and Central America Appendix B: South America Appendix C: Europe Appendix D: Africa Appendix E: Eurasia Appendix F: Asia Appendix G: Oceania References Index.

/pdf/river-discharge-to-the-coastal-ocean-a-global-synthesis-571z1g19ts.pdf

River Discharge to the Coastal Ocean: A Global Synthesis

https://www.meas.ncsu.edu/sealevel/publications/Liu_Yangtze_2007_Geomorphology.pdf

Flux and fate of Yangtze River sediment delivered to the East China Sea

50,000 dams later: Erosion of the Yangtze River and its delta

[1] In 5 recent years (2000–2004), the Changjiang (Yangtze) River has discharged past Datong (600 km from the river mouth) an average of ∼250 million tons (mt) of sediment per year, a decrease of more than 40% since the 1950s and 1960s, whereas water discharge at Datong has increased slightly. Water and sediment discharge data from the upper, middle, and lower reaches of the river suggest that the reduction of the Changjiang sediment load has occurred in two phases between 1950 and 2002: following the closure of the Danjiangkou Reservoir on the Hanjiang tributary in 1968 and following the installation of numerous dams and water-soil conservation works in the Jialingjijang catchment after 1985. As the Three Gorges Dam (TGD) started operating in 2003, the Changjiang entered a third phase of sediment reduction with annual sediment loads at Datong less than 200 mt/yr. Upon completion of the Three Gorges Dam (TGD) in 2009, the sediment load at Datong will decrease to ∼210 mt/yr for the first 20 years, then will recover to ∼230 mt/yr during 2030–2060, and will reach ∼310 mt/yr during 2060–2110. From the sediment budget and sediment erosion data for the Changjiang subaqueous delta, it can be assumed that the delta will be eroded extensively during the first five decades after TGD operation and then will approach a balance during the next five decades as sediment discharging from TGD again increases.

/pdf/dam-impacts-on-the-changjiang-yangtze-river-sediment-44qx49bu6q.pdf

Dam impacts on the Changjiang (Yangtze) River sediment discharge to the sea: The past 55 years and after the Three Gorges Dam

Yangtze River of China: historical analysis of discharge variability and sediment flux

With intense anthropogenic perturbations in the Changjiang (Yangtze) River basin, the riverine loads and compositions of materials into the Changjiang Estuary have greatly changed, resulting in dramatic deterioration in the Changjiang Estuary and adjacent sea environments. Based on a long-term data set of the material loads into the Changjiang Estuary, changing trends and associated impacted factors were presented. The results showed downward trends concentrations and loads of dissolved silicate (DSi) over the past 50 years due to dam constructions in the Changjiang River. However, dissolved nitrogen (DIN) and dissolved inorganic phosphate (DIP) exhibited remarkable upward trends due to the increase of the population and the use of large-scale chemical fertilizer in the Changjiang River basin. The sharp decrease in the ratio of DSi/DIN and the increase in the ratio of DIN/DIP could cause increased Red tide bloom and decreased dissolved oxygen in the Changjiang Estuary. In addition, even though water discharge has remained almost constant, the suspended sediment discharge was shown to be sharply decreased due to the construction of dams.

Variation of Riverine Material Loads and Environmental Consequences on the Changjiang (Yangtze) Estuary in Recent Decades (1955−2008)†

[1] In 2006, the Changjiang basin runoff reached its lowest level in the last 50 years, and the water level in the Three Gorges Dam (TGD) was raised from 135 m to 156 m. Based on routine water level and runoff measurements at 10 field stations, the water level in flood season during the last 50 years was lowest in 2006, a situation here we describe as “no flood in the flood season” (NFFS). In contrast, there was no obvious change in runoff of the mid-lower reaches of the Changjiang river (MLRCR) in the drought season in 2006, which we correspondingly describe as “no drought in the drought season (NDDS)”. The extreme drought of Changjiang and impounding of TGD contributed to NFFS. However, the adjustment of TGD and the replenishment from tributaries and lakes resulted in NDDS. Meanwhile, 54% of the water flux was lost at Datong during September 20 to October 27, 2006, in comparison with the same period in 2005. It can be estimated that the impounding of TGD and the extreme drought in 2006 contributed 9% and 45% of this loss, respectively.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008GL033456

Jiufa Li

Papers

Yangtze River of China: historical analysis of discharge variability and sediment flux

Variation of Riverine Material Loads and Environmental Consequences on the Changjiang (Yangtze) Estuary in Recent Decades (1955−2008)†

Runoff characteristics of the Changjiang River during 2006: Effect of extreme drought and the impounding of the Three Gorges Dam

Sediment resuspension and implications for turbidity maximum in the Changjiang Estuary

Effects of navigational works on morphological changes in the bar area of the Yangtze Estuary