ERA-CLIM Historical Upper-Air Data 1900-1972

Historical, i.e. pre-1957, upper-air data are a valuable source of information on the state of the atmosphere, in some parts of the World back to the early 20th century. However, to date reanalyses have only partially made use of these data, and only of observations made after 1948. Even for the period between 1948 (the starting year of the NCEP/NCAR reanalysis) and the International Geophysical Year in 1957 (the starting year of the ERA-40 reanalysis), when the global upper-air coverage reached more or less its current status, many observations have not been digitised until now. The Comprehensive Historical Upper-Air Network (CHUAN) already compiled a large collection of pre-1957 upper-air data. In the framework of the European project ERA-CLIM, significant amounts of additional upper-air data have been catalogued (> 1.3 mio station days), imaged (> 200,000 images) and digitised (> 700,000 station days) in order to prepare a new input dataset for upcoming reanalyses. The records cover large parts of the globe, focussing on so far less well covered regions such as the Tropics, the polar regions and the Oceans, and on very early upper-air data from Europe and the US. The total number of digitised/inventoried records is 61/101 for moving upper-air data, i.e. data from ships etc., and 735/1,783 for fixed upper-air stations. Here, we give a detailed description of the resulting dataset including the metadata and the quality checking procedures applied. The data will be included in the next version of CHUAN.

Mangrove cover in the Red Sea (1972-2013)

Across the Earth, mangroves play an important role in coastal protection, both as nurseries and carbon sinks. However, due to various human and environmental impacts, the coverage of mangroves is declining on a global scale. The Red Sea is in the northern-most area of the distribution range of mangroves. Little is known about the surface covered by mangroves at this northern limit or about the changes experienced by Red Sea mangroves. We sought to study changes in the coverage of Red Sea mangroves by using multi-temporal Landsat data (1972, 2000 and 2013). Interestingly, our results show that there has been no decline in mangrove stands in the Red Sea but rather a slight increase. The area covered by mangroves is about 69 km**2 along the African shore and 51 km**2 along the Arabian Peninsula shore. From 1972 to 2013, the area covered by mangroves increased by about 0.29%/y. We conclude that the trend exhibited by Red Sea mangroves departs from the general global decline of mangroves. Along the Red Sea, mangroves expanded by 12% over the 41 years from 1972 to 2013. Losses to Red Sea mangroves, mostly due to coastal development, have been compensated by afforestation projects.

Description and chemical composition of manganese deposits during the deep-sea expedition of the streamer Valdivia in 1898-1899

This monograph forms the fourth part of the tenth volume of the scientific results of the voyage of the German exploring ship Valdivia in the Atlantic and Indian Oceans, made during the years 1898-1899. These volumes are published under the editorship of Prof. Chun, the zoologist of Leipzig, who was leader of the expedition ; and Prof. E. Philippi with the cooperation of Sir John Murray. The nature of the materials brought up at various points during the voyage is well illustrated by a series of plates, similar to those accompanying the Challenger volumes. Among the concretions from the Agulhas Bank were found phosphatic nodules containing 33 per cent, of calcium carbonate, 28 of calcium phosphate, 14.6 of calcium sulphate, and 4.8 of magnesium carbonate, with some ferric oxide, alumina, and silica. These nodules were dredged at a depth of 155 metres. Off the coast of Namibia, a large quantity of manganese nodules were also dredged. Their chemical analysis performed at the Mineralogical Institute of the University Jena show similar composition as the nodules recovered by the "Challenger" at station 253 in the Pacific Ocean.