The long-term trend of the sea surface wind speed and the wave height (wind wave, swell, mixed wave) in global ocean during the last 44 a

Utilizing the 45 a European Centre for Medium-Range Weather Forecasts （ECMWF） reanalysis wave da- ta （ERA-40）, the long-term trend of the sea surface wind speed and （wind wave, swell, mixed wave） wave height in the global ocean at grid point 1.5°× 1.5° during the last 44 a is analyzed. It is discovered that a ma- jority of global ocean swell wave height exhibits a significant linear increasing trend （2-8 cm/decade）, the distribution of annual linear trend of the significant wave height （SWH） has good consistency with that of the swell wave height. The sea surface wind speed shows an annually linear increasing trend mainly con- centrated in the most waters of Southern Hemisphere westerlies, high latitude of the North Pacific, Indian Ocean north of 30°S, the waters near the western equatorial Pacific and low latitudes of the Atlantic waters, and the annually linear decreasing mainly in central and eastern equator of the Pacific, Juan. Fernandez Archipelago, the waters near South Georgia Island in the Atlantic waters. The linear variational distribution characteristic of the wind wave height is similar to that of the sea surface wind speed. Another find is that the swell is dominant in the mixed wave, the swell index in the central ocean is generally greater than that in the offshore, and the swell index in the eastern ocean coast is greater than that in the western ocean inshore, and in year-round hemisphere westerlies the swell index is relatively low.

An assessment of global ocean wave energy resources over the last 45 a

Against the background of the current world facing an energy crisis,and human beings puzzled by the problems of environment and resources,developing clean energy sources becomes the inevitable choice to deal with a climate change and an energy shortage.A global ocean wave energy resource was reanalyzed by using ERA-40 wave reanalysis data 1957–2002 from European Centre for Medium-Range Weather Forecasts（ECMWF）.An effective significant wave height is defined in the development of wave energy resources（short as effective SWH）,and the total potential of wave energy is exploratively calculated.Synthetically considering a wave energy density,a wave energy level probability,the frequency of the effective SWH,the stability and long-term trend of wave energy density,a swell index and a wave energy storage,global ocean wave energy resources were reanalyzed and regionalized,providing reference to the development of wave energy resources such as wave power plant location,seawater desalination,heating,pumping.

Trends in Vegetation Response to Drought in Sudano-Sahelian Part of Northern Nigeria

This study was carried out to evaluate the drought occurrence and its implication on vegetation cover over the Sudano-Sahelian zone of the Northern part of Nigeria. Monthly mean Rainfall data for the period 40 years (1971-2010) were obtained from Nigeria Meteorological Agency (NIMET) for each of the meteorological stations present and functioning in this region for climatic analysis. Standardized Precipitation Index (SPI) was used to analyze drought occurrence on a time scale of five (5) months that cover the period of raining season over the study area. Also Satellite data over the selected part of the study area for three different epochs, 1986, 2000 and 2005 were used for vegetation response analysis. The SPI values were interpolated using Inverse Distance Weighted (IDW) interpolation technique in ArcGIS 9.3 to generate Drought Spatial Pattern Map for each selected modeled years. The vegetation response indicators used are land cover maps and Greenness Index (GI) maps. Land cover categories were classified into five levels: Dense Vegetation, less dense Vegetation, Settlement/built up, Bare Surface and Water body. The results based on the ground truth (rainfall) data show that many years of drought episode were experienced over the study area. On the other hand, the prime indicators (Land cover and GI maps) used in this study also depicts the changes that took place over the study area in response to this climatic anomaly (drought) and it could be noted that there was dramatic reduction in the occurrence towards the end of the last two decade, 1990-1999, which simply indicated improvement in rainfall even in 2000 and the later years.

The Influence of Sea Surface Temperatures on Uganda's Rainfall

Uganda’s rainfall is controlled by large scale patterns and synoptic-scale weather features such as the Inter Tropical Convergence Zone(ITCZ), monsoons,meso-scale circulations,subtropical anticyclones and teleconnections.This study focused on the influence of sea surface temperatures(SSTs)on Uganda’s March-May(MAM)and September-November (SON)rains.The data used included

Best Practices and Lessons Learned in the Implementation of Global Framework for Climate Services—Adaptation Programme in Africa: Tanzania-Experience

This paper provides an analysis and a description of the best practices and lessons learned in the implementation of the Global Framework for Climate Services Adaptation Program in Africa (GFCS-APA) focusing on Tanzania country’s activities. GFCS-APA was the first multi-agency initiative implemented under the Global Framework for Climate Services (GFCS) in two African countries, namely Tanzania and Malawi with funding from the Royal Government of Norway. In Tanzania, the programme was implemented in two phases from the year 2014 to 2021 in the three pilot districts of Kondoa, Longido and Kiteto located in Dodoma, Arusha and Manyara regions, respectively. The overarching goal of the programme was to enable better management of the risks caused by climate variability and change at all levels, from end-users to policy level, through development and incorporation of science-based climate information and prediction services into planning, policy and practice. The programme focused on bridging the gap between providers and users of climate information and products through development of user-driven climate services for food security, health and disaster risk reduction. This paper aimed to analyze lessons learned and best practices in the course of the implementation of the GFCS-APA phase I and II in Tanzania. A qualitative approach was employed to analyze the lessons learned and best practices, by extracting them and exploring further on their contribution to the enhancement of climate services, as well as their applicability and potentiality for scaling out in other regions within Tanzania, and in other countries. The results indicate the identified best practices and lessons learned contributed significantly in enhancing climate services, particularly in understanding, availability, accessibility, utilization, ownership and sustainability of climate services among users (farmers and pastoralists) of various gender, as well as intermediaries and decision-makers. Results also indicate the lessons learned and the documented best practices could influence the effectiveness of climate services in other areas, to address existing challenges in access, uptake and sustainability of climate services. The best practices and lessons learned could be considered for integration in the future projects or operational activities in other regions within the country and other countries, particularly in the developing world, including Sub-Saharan Africa.

Dominant Synoptic Patterns and Their Relationships with PM2.5 Pollution in Winter over the Beijing–Tianjin–Hebei and Yangtze River Delta Regions in China

This paper concerns about the episodes of PM2.5 pollution that frequently occur in China in winter months.The severity of PM2.5 pollution is strongly dependent on the synoptic-scale atmospheric conditions.We combined PM2.5 concentration data and meteorological data with the Hybrid Single Particle Lagrangian Integrated Trajectory model(HYSPLIT4)to investigate the dominant synoptic patterns and their relationships with PM2.5 pollution over the Beijing–Tianjin–Hebei(BTH)and Yangtze River Delta(YRD)regions in the winters of 2014–17.The transport of PM2.5 from the BTH to YRD regions was examined by using cluster analysis and HYSPLIT4.It is found that the level of PM2.5 pollution over the BTH region was higher than that over the YRD region.The concentration of PM2.5 in the atmosphere was more closely related to meteorological factors over the BTH region.The episodes of PM2.5 pollution over the BTH region in winter were related to weather patterns such as the rear of a high-pressure system approaching the sea,a high-pressure field,a saddle pressure field,and the leading edge of a cold front.By contrast,PM2.5 pollution episodes in the YRD region in winter were mainly associated with the external transport of cold air,a high-pressure field,and a uniform pressure field.Cluster analysis shows that the trajectories of PM2.5 were significantly different under different weather patterns.PM2.5 would be transported from the BTH to the YRD within 48 h when the PM2.5 pollution episodes were associated with three different kinds of weather patterns:the rear of a highpressure system approaching the sea,the high-pressure field,and the leading edge of a cold front over the BTH region.This suggests a possible method to predict PM2.5 pollution episodes based on synoptic-scale patterns.