Prediction of River Water Temperature and its Dependence on Hydro-Meteorological Factors

Aldona Jurgelėnaitė,Darius Jakimavičius

doi:10.5755/j01.erem.68.2.6178

Aldona Jurgelėnaitė, Darius Jakimavičius

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https://doi.org/10.5755/j01.erem.68.2.6178

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Abstract

Rivers will be among the most sensitive of all ecosystems to the effects of climate change as they are heated by processes similar to those warming the Earth's atmosphere. The river water and air temperatures follow each other closely. The life cycle of lotic biota is regulated by two major physical factors: water temperature and hydraulic conditions. Any change in hydraulic pattern that leads to an alteration of the established thermal regime of a lotic ecosystem will ultimately lead to a dramatic change in the composition and survival of lotic biota. In order to assess the impacts of potential climate change on thermal regime of water bodies, it is important to know the long range forecasts for various climatic parameters. For this purpose the modelling of water discharge and forecasting of future changes are performed. This paper provides the long-term changes in the Lithuanian river water temperature according to two models and emissions scenarios. This paper evaluates the changes of warm season (May-October) water temperature and heat runoff of Lithuanian rivers (Nemunas, Merkys and Dubysa) with different thermal regimes at the end of the 21st century (2071–2100) comparing to the climate normal period (1961-1990) using two climate change models (ECHAM5 and HadCM3 global climate models and the A2 and B1 emissions scenarios) and hydrological modelling (HBV model). DOI: http://dx.doi.org/10.5755/j01.erem.68.2.6178

Highlights

There is a growing consensus among environmental scientists that the Earth experiences a gradual increase in temperature
Weak positive correlations were obtained between water temperature and precipitation, whereas weak negative relationships were between the water temperature and discharge
Climate change is expected mostly to affect the runoff of smaller rivers, especially increasing runoff in the summer months (JuneAugust) from 4% to 49%, depending on the model and emissions scenario

Summary

Introduction

There is a growing consensus among environmental scientists that the Earth experiences a gradual increase in temperature. There are persuasive reasons for believing that rivers will be among the most sensitive of all ecosystems to the effects of climate change. They are heated by processes similar to those warming the Earth's atmosphere, and river water and air temperatures follow each other closely (Caissie 2006). In addition to these thermal effects, river ecosystems are directly influenced by water discharge of the river, precipitation and other hydrometeorological influences. Climate change increasingly modifies the temporal variability of a river flow; ecological effects will be unavoidable

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