Regionalization of maximum, minimum and mean streamflows for the Juruena River basin, Brazil

This study aimed to regionalize maximum (Qmax), minimum (Q95), and long-term mean (Qltm) streamflows in the Juruena River Basin to further water-resource planning and management, especially regarding water-use grant rights, streamflow regulation, and hydraulic designs. To do that, a traditional method was used, which relates the interest streamflows with sub-basin physiographic parameters by linear and nonlinear regressions. In summary, the traditional method was efficient for regionalization of Q95, Qltm, and Qmax streamflows for the Juruena River Basin. Moreover, the explanatory variables able to provide the best results for regionalization of Q95 and Qltm stream flows are drainage area, total watercourse length, and sub-basin mean altitude. For Qmax regionalization, the best results were provided by explanatory variables like drainage area, perimeter, and total watercourse length.

Caracterização Fisiográfica da Sub-Bacia do Riacho Jacaré – SE

O Riacho Jacaré é um afluente do Rio São Francisco, está localizado em sua margem direita e apresenta grande relevância para a região Norte do Estado de Sergipe. A Sub-Bacia do Riacho Jacaré ao longo dos anos vem sofrendo graves processos de degradação ambiental, devido principalmente à má utilização do solo e dos recursos hídricos. Esse processo originou-se devido principalmente à falta de planejamento relacionado à utilização do uso e ocupação do solo na região. O presente trabalho tem como objetivo fornecer os parâmetros fisiográficos da Sub-Bacia do Riacho Jacaré, a fim de, favorecer práticas futuras relacionadas ao uso e ocupação do solo e da água, baseado em um planejamento ambiental adequado referente à conservação dos recursos naturais presentes. Os resultados demonstram que a sub-bacia, está sujeita parcialmente a processos de enchentes devido a sua forma aos fatores relacionados com o coeficiente de compacidade de 1,43 e ao fator forma de 0,47.Palavras-chave: Planejamento ambiental, geoprocessamento, enchentes. ABSTRACT The Riacho Jacaré is a tributary of the Rio Sao Francisco, is located in the right margin and are highly relevant to the region north of the state of Sergipe. Sub-Basin of Riacho Jacaré over the years has been suffering severe environmental degradation processes, mainly due to poor land use and water resources. This paper aims to provide the physiographic parameters of the Sub-Basin of Riacho Jacaré in order to encourage practices related to the use and occupation of land and water, based on an adequate environmental planning on the conservation of natural resources present. The results show that the Sub-Basin, is subject to partial flooding processes due to their form factors related to the compactness coefficient of 1.43 and the shape factor of 0.47. Keywords: Environmental planning, GIS, flood.

Evaluation of high-resolution forecasts with the non-hydrostaticnumerical weather prediction model Lokalmodell for urban air pollutionepisodes in Helsinki, Oslo and Valencia

The operational numerical weather prediction model Lokalmodell LM with 7 km horizontal resolution was evaluated for forecasting meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speeds for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length). The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer and diffusion coefficients. The LM simulations distinctly improved for winter daytime and nocturnal spring and autumn inversions and showed good skill at forecasting further episode-relevant meteorological parameters. The evaluation of the photochemical Valencia episode concentrated on the dominating mesoscale circulation patterns and showed that the LM succeeds well in describing all the qualitative features observed in the region. LM performance in forecasting the examined episodes thus depends on the key episode characteristics and also the season of the year with a need to improve model performance in very stable inversion conditions not only for urban simulations.

Evaluation of very high-resolution simulations with the non-hydrostatic numerical weather prediction model Lokalmodell for urban air pollution episodes in Helsinki, Oslo and Valencia

The operational numerical weather prediction model Lokalmodell LM with 7 km horizontal resolution was evaluated for simulations of the meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speed for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length). The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer and diffusion coefficients. The LM simulations distinctly improved for winter daytime and nocturnal spring and autumn inversions and showed good skill at forecasting further episode-relevant meteorological parameters. The evaluation of the photochemical Valencia episode concentrated on the dominating mesoscale circulation patterns and showed that the LM succeeds well in describing all the qualitative features observed in the region. LM performance in forecasting the examined episodes thus depends on the key episode characteristics and also the season of the year with a need to improve model performance in very stable inversion conditions not only for urban simulations.