Elevation-Dependent Trends in Precipitation Observed over and around the Tibetan Plateau from 1971 to 2017

The Tibetan Plateau (TP) are regions that are most sensitive to climate change, especially extreme precipitation changes with elevation, may increase the risk of natural disasters and have attracted attention for the study of extreme events in order to identify adaptive actions. Based on daily observed data from 113 meteorological stations in the Tibetan Plateau and the surrounding regions in China during 1971–2017, we calculated the annual total precipitation and extreme precipitation indices using the R ClimDex software package and explored elevation-dependent precipitation trends. The results demonstrate that the annual total precipitation increased at a rate of 6.7 mm/decade, and the contribution of extreme precipitation to total precipitation increased over time, and the climate extremes were enhanced. The annual total, seasonal precipitation, and precipitation extreme trends were observed in terms of elevation dependence in the Tibetan Plateau (TP) and the surrounding area of the Tibetan Plateau (TPS) during 1971–2017. There is growing evidence that the elevation-dependent wetting (EDWE) is complex over the TP. The trends in total precipitation have a strong dependence on elevation, and the EDWE is highlighted by the extreme precipitation indices, for example, the number of heavy precipitation days (R10) and consecutive wet days (CWD). The dependence of extreme precipitation on elevation is heterogeneous, as other extreme indices do not indicate EDWE. These findings highlight the precipitation complexity in the TP. The findings of this study will be helpful for improving our understanding of variabilities in precipitation and extreme precipitation in response to climate change and will provide support for water resource management and disaster prevention in plateaus and mountain ranges.

Assessment of changes in air temperature and precipitation in Transbaikalia

Assessment of changes in air temperature and precipitation in Transbaikalia/ Smakhtin V.K. // Hydrometeorological Research and Forecasting, 2021, no. 2 (380), pp. 138-146. The paper analyzes long-term fluctuations in average air temperature and annual total precipitation in Transbaikalia. Between 1951 and 2020, air temperature increased by 2.3 °C according to 40 weather stations. Warming is mainly manifested in the air temperature rise in February, March and April. From 1955 to 2017, the decrease in annual total precipitation was 56 mm in the Amur basin and 39 mm in the Yenisei basin. The trends are reliable at the 5% significance level. In the Lena basin, annual total precipitation during the mentioned period increased by 7 mm, the trend is not reliable at the 5% significance level. The high-water phase has been observed since 2017. Taking into account that two previous high-water phases lasted 16‒17 years, it may be supposed that a risk of precipitation above the normal will be kept in the next 13–14 years. Keywords: climate change, air temperature, precipitation, phases of water content, trendsRef. 81.

THE REGIONAL DIFFERENCES OF GPP ESTIMATION BY SOLAR INDUCED FLUORESCENCE

Estimating gross primary productivity (GPP) at large spatial scales is important for studying the global carbon cycle and global climate change. In this study, the relationship between solar-induced chlorophyll fluorescence (SIF) and GPP is analysed in different levels of annual average temperature and annual total precipitation respectively using simple linear regression analysis. The results showed high correlation between SIF and GPP, when the area satisfied annual average temperature in the range of −5 °C to 15 °C and the annual total precipitation is higher than 200 mm. These results can provide a basis for future estimation of GPP research.

Providing a non-deterministic representation of spatial variability of precipitation in the Everest region

This paper provides a new representation of the effect of altitude on precipitation that represents spatial and temporal variability in precipitation in the Everest region. Exclusive observation data are used to infer a piecewise linear function for the relation between altitude and precipitation and significant seasonal variations are highlighted. An original ensemble approach is applied to provide non-deterministic water budgets for middle and high-mountain catchments. Physical processes at the soil–atmosphere interface are represented through the Interactions Soil–Biosphere–Atmosphere (ISBA) surface scheme. Uncertainties associated with the model parametrization are limited by the integration of in situ measurements of soils and vegetation properties. Uncertainties associated with the representation of the orographic effect are shown to account for up to 16 % of annual total precipitation. Annual evapotranspiration is shown to represent 26 % ± 1 % of annual total precipitation for the mid-altitude catchment and 34% ± 3 % for the high-altitude catchment. Snowfall contribution is shown to be neglectable for the mid-altitude catchment, and it represents up to 44 % ± 8 % of total precipitation for the high-altitude catchment. These simulations on the local scale enhance current knowledge of the spatial variability in hydroclimatic processes in high- and mid-altitude mountain environments.

Providing a non-deterministic representation of spatial variability of precipitation in the Everest region

This paper provides a new representation of the effect of altitude on precipitation that represent spatial and temporal variability of precipitation in the Everest region. Exclusive observation data are used to infer a piecewise linear function for the relation between altitude and precipitation and significant seasonal variations are highlighted. An original ensemble approach is applied to provide non deterministic water budgets for middle and high mountain catchments. Physical processes at the soil-atmosphere interface are represented through the ISBA surface scheme. Uncertainties associated with the model parametrization are limited by the integration of in-situ measurements of soils and vegetation properties. Uncertainties associated with representation of the orographic effect are shown to account for up to 16 % of annual total precipitation. Annual evapotranspiration is shown to represent 26 % ± 1 % of annual total precipitation for the mid-altitude catchment and 34 % ± 3 % for the high-altitude catchment. Snow fall contribution is shown to be neglectible for the mid-altitude catchment and it represents up to 44 % ± 8 % of total precipitation for the high-altitude catchment. These simulations at the local scale enhance current knowledge of the spatial variability of hydro-climatic processes in high- and mid-altitude mountain environments.

Cenários de Mudanças Climáticas no Estado da Bahia através de Estudos Numéricos e Estatísticos (Climate Change Scenarios in Bahia through Numerical and Statistical Studies)

Este trabalho teve como objetivo investigar a ocorrência ou ausência de mudanças climáticas no período de 1970 a 2006, em algumas microrregiões do estado da Bahia: Irecê, Oeste, Sudoeste e Baixo Médio São Francisco, através de índices de tendências de mudanças climáticas obtidos da precipitação pluviométrica e das temperaturas máxima e mínima diárias das estações climatológicas das respectivas regiões e de cenários de mudanças climáticas. Utilizou-se os índices de detecção de mudanças climáticas sugeridos pela OMM calculados a partir dos dados de precipitação e das temperaturas máxima e mínima diárias através do software RClimdex 1.9.0. No estudo numérico foi utilizado o modelo BRAMS. Observou-se que na região de Irecê houve tendência de diminuição da precipitação total anual e aumento da intensidade das chuvas diárias. Na região Oeste houve aumento no número de dias com temperaturas elevadas, aumento nas temperaturas mínimas diárias e aumento na intensidade das chuvas. Na região Sudoeste houve uma tendência de um pequeno aumento dos totais anuais de chuvas. Na região do Baixo Médio São Francisco houve aumento no número de dias com temperatura máxima diária, diminuição das chuvas diárias e da precipitação total anual. Essa variação na precipitação na região pode ser atribuída à circulação de grande escala, enquanto a intensidade das chuvas pode ter influência na variabilidade climática. Cabe aos gestores desse país encarar essa realidade com muita responsabilidade e, sugira ações e medidas eficazes para combatê-la, capacitando a sociedade como um todo para conviver com essa nova realidade. Palavras-chave: Mudanças climáticas; estudos numéricos; índices de tendências climáticas. Climate Change Scenarios in Bahia through Numerical and Statistical Studies ABSTRACT This work had as objective to investigate the occurrence or absence of climatic changes in the period of 1970 the 2006, in some microregions of the state of the Bahia: Irecê, Oeste, Sudoeste and Baixo Médio São Francisco, through indexes of trends of climatic changes with data of daily total precipitation and the daily temperatures maximum and minimum of the climatological stations of the respective regions and climate change scenarios. One used the indexes of detection of climatic changes suggested by WMO calculated from the data of daily precipitation and the daily temperature through software RClimdex 1.9.0. The study used numerical model BRAMS. It was observed that in the region of Irecê it had trend of reduction of the annual total precipitation and increase in the intensity of daily rains. In the region Oeste it had increase in the number of days with raised temperatures, increase in the daily minimum temperatures and increase in the intensity of rains. In the Sudeste region it had a trend of a small increase of the annual rain totals. In the region of the Baixo Médio São Francisco it had increase the number of days with daily maximum temperature, reduction of daily rains and the annual total precipitation. This variation in the precipitation in the region can be attributed to the circulation of great scale, while the intensity of rains can have influence in the climatic variability. It is the managers of this country face that reality as something that must be faced with great responsibility, and suggest actions and effective measures to combat it enabling the society as a whole to deal with this new reality.Keywords: Climatic changes; numerical studies; climate trends.

Vegetation Activity Trend and Its Relationship with Climate Change in the Three Gorges Area, China

Based on SPOT/VGT NDVI time series images from 1999 to 2009 in the Three Gorges Area (TGA), we detected vegetation activity and trends using two methods, the Mann-Kendall and Slope tests. The relationships between vegetation activity trends and annual average temperature and annual total precipitation were analyzed using observational data in seven typical meteorological stations. Vegetation activity presents a distinctive uptrend during the study period, especially in Fengjie, Yunyang, Wushan, Wuxi, and Badong counties located in the midstream of the Three Gorges Reservoir. However, in the Chongqing major area (CMA) and its surrounding areas and Fuling, Yichang, and part of Wanzhou, vegetation activity shows a decreasing trend as a result of urban expansion. The NDVI has two fluctuation troughs in 2004 and 2006. The annual mean temperature presents a slight overall upward trend, but the annual total precipitation does not present a significant trend. And they almost have no significant correlations with the NDVI. Therefore, temperature and precipitation are not major influences on vegetation activity change. Instead, increasing vegetation cover benefits from a number of environment protection policies and management, and ecological construction is a major factor resulting in the upward trend. In addition, resettlement schemes mitigate the impact of human activity on vegetation activity.

New precipitation and accumulation maps for Greenland

Annual total precipitation and the annual accumulation on the Greenland ice sheet are evaluated and presented in two maps. The maps are based on accumulation measurements of 251 pits and cores obtained from the upper accumulation zone and precipitation measurements made at 35 meteorological stations in the coastal region. To construct the accumulation map, the annual precipitation was split into solid and liquid precipitation components. Annual total precipitation exceeding 2500mmw.e. occurs on the southeastern tip of Greenland, while the minimum precipitation is estimated to occur on the northeastern slope of the ice sheet. The mean annual precipitation for all of Greenland is 340 mm w.e. The largest annual accumulation of about 1500 mm w.e. is found on the glaciers in the southeastern corner of Greenland, while the smallest accumulation is found on the northeastern slope of the ice sheet west of Danmarkshavn. The mean accumulation on the Greenland ice sheet is estimated at 310mmw.e. The regional difference in accumulation is examined with respect to the 850hPa(mbar) level circulation. The present surface topography is found to play an important role in determining regional accumulation on the ice sheet.

New precipitation and accumulation maps for Greenland

Annual total precipitation and the annual accumulation on the Greenland ice sheet are evaluated and presented in two maps. The maps are based on accumulation measurements of 251 pits and cores obtained from the upper accumulation zone and precipitation measurements made at 35 meteorological stations in the coastal region. To construct the accumulation map, the annual precipitation was split into solid and liquid precipitation components. Annual total precipitation exceeding 2500mmw.e. occurs on the southeastern tip of Greenland, while the minimum precipitation is estimated to occur on the northeastern slope of the ice sheet. The mean annual precipitation for all of Greenland is 340 mm w.e. The largest annual accumulation of about 1500 mm w.e. is found on the glaciers in the southeastern corner of Greenland, while the smallest accumulation is found on the northeastern slope of the ice sheet west of Danmarkshavn. The mean accumulation on the Greenland ice sheet is estimated at 310mmw.e. The regional difference in accumulation is examined with respect to the 850hPa(mbar) level circulation. The present surface topography is found to play an important role in determining regional accumulation on the ice sheet.