The history of radio telescopes, 1945–1990

Forged by the development of radar during World War II, radio astronomy revolutionized astronomy during the decade after the war. A new universe was revealed, centered not on stars and planets, but on the gas between the stars, on explosive sources of unprecedented luminosity, and on hundreds of mysterious discrete sources with no optical identifications. Using “radio telescopes” that looked nothing like traditional (optical) telescopes, radio astronomers were a very different breed from traditional (optical) astronomers. This pathbreaking of radio astronomy also made it much easier for later “astronomies” and their “telescopes” (X-ray, ultraviolet, infrared, gamma-ray) to become integrated into astronomy after the launch of the space age in the 1960s. This paper traces the history of radio telescopes from 1945 through about 1990, from the era of converted small-sized, military radar antennas to that of large interferometric arrays connected by complex electronics and computers; from the era of strip-chart recordings measured by rulers to powerful computers and display graphics; from the era of individuals and small groups building their own equipment to that of Big Science, large collaborations and national observatories.     

Drainage-basin evolution and aquifer development in a karstic limestone terrain South-Central Texas,U.S.A.

The Edwards artesian aquifer occurs in cavernous limestones of Cretaceous (Albian) age within the Balcones fault zone in south-central Texas. The major recharge and discharge zones of the aquifer are contained within the upper reaches of three river systems: the Nueces, the San Antonio, and the Guadalupe. Within these watersheds, recharge dominates in the semiarid Nueces basin to the west while most discharge occurs farther east from wells in the subhumid San Antonio basin and from springs in the subhumid Guadalupe basin. This long-distance transfer of ground water (up to 240 km) is a result of several factors: depositional and early diagenetic history of the limestone host rock, geometry and magnitudes of fault displacement, and physiographic responses to faulting. The loci of greatest discharge from the aquifer occur in an area that was exposed subaerially with concomitant porosity enhancement due to dissolution of limestone during late Early Cretaceous time. This area also was subjected to the greatest fault displacement during Miocene time. Thus, faults and associated joints superimposed additional avenues for porosity and permeability development onto an area that already had considerable secondary porosity. Further determinants on aquifer properties resulted from late Tertiary and Quaternary drainage evolution in response to faulting along the Balcones trend. The strike of the fault zone lay at acute angles to the courses of the main trunk streams in the ancestral Guadalupe and San Antonio River systems, whereas in the Nueces basin the trend of the fault zone was normal to the courses of the main streams. Thus, as a fault-line scarp began to form in the eatern basins, scarp-normal streams were incised rapidly into northwest-trending canyons. These steep-gradient streams captured the eastward-flowing major streams in the easten watersheds. These pirate streams incised into the aquifer at the lowest topographic levels within the region because of: 1. The sudden acquisition of extensive catchment areas in a subhumid area; and 2. Steep stream gradients that reflected the larger fault displacement in the east. The low topographic points of discharge became the loci of major springs. Recharge is dominant in the Nueces basin mainly because streams cross permeable limestone units at higher topographic levels than in the San Antonio and Guadalupe basins. The topographic characteristics of the Nueces watershed resulted from a combination of diverse factors: lesser fault displacement, no major stream piracy, and less vigorous erosion because of a semiarid climate.     

The burrowing behavior of sand lance, Ammodytes hexapterus: Effects of oil-contaminated sediment

Whilst foraging in the water column for zooplankton, sand lance, Ammodytes hexapterus, are under heavy predation from marine birds and fish. To avoid predation, sand lance bury in the sand when not foraging and during overwintering. We did two experiments to determine whether oil contamination of the sand would reduce the amount of time that sand lance spent buried. In the first experiment (June, 1980) sand lance significantly decreased by 20% the time spent buried in oiled sand (306 ppm). In the second experiment (June, 1981) sand lance did not decrease time spent buried in oiled sand at 28 and 256 ppm but did at 3384 ppm. The higher condition index of the 1981 fish suggested that nutritional state may have influenced how sand lance used the sediment as a refuge and how they responded to contamination of that refuge.     

Early Ship Observational Data and Icoads

Many surface marine meteorological observations (∼125 million) from ships' logbooks have been assembled in the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) back to the late 18th century. We describe the makeup of the available data before 1950, and a recent update for that period incorporating a variety of US and international sources – focusing on the background, digitization, and processing of the US Maury Collection, which provides the earliest data (mainly 1830–1860) currently blended into ICOADS. We also describe planned data and metadata additions to early ICOADS. Among these, the new Climatological Database for the World's Oceans (CLIWOC) will extend and enhance coverage for 1750–1854. Prospects for data improvements and homogeneity enhancements to further benefit climate research are also discussed.     

Evidence for elevated coastal vulnerability following large‐scale historical oyster bed harvesting

Living coastal barriers, such as coral reefs, tidal marshes, mangroves and shellfish beds are widely recognized for their potential role in mitigating flood risk. Limited data exists, however, for assessing the effectiveness of these natural defenses as forms of flood mitigation. In particular, very few mature shellfish beds exist today for modern study due to their destruction in the past few centuries. As an alternative method of study, we present here sedimentary reconstructions of storm overwash from coastal ponds internal to New York Harbor. We use these reconstructions to show that the initial degradation of oyster beds following European settlement of the area coincides with a significant increase in wave‐derived overwash deposition at all three of our field sites. Numerical simulations of two flood events of record in the harbor (Hurricane Sandy and a severe winter storm in 1992) were run without and with oyster beds of varying heights (1 m above the seafloor‐to‐intertidal). Simulations show that the removal of these oyster beds increases wave energy directly off‐shore of our field sites by between 30% and 200%. Sedimentary reconstructions and wave modeling experiments therefore both support oyster beds serving as a significant form of coastal protection prior to European disturbance. Copyright © 2016 John Wiley & Sons, Ltd.     

South Atlantic winds and weather during and following the little ice age — A pilot study of English East India Company (EEIC) ship logs

Summary The times taken by ships of the English East India Company (EEIC) to sail from the Cape of Good Hope to St. Helena Island during the 17th, 18th, and early 19th centuries represent proxy measures of the strength and steadiness of the Southeast Trades which are compared with present-day data from the Comprehensive Ocean-Atmosphere Data Set (COADS). Both wind speed and steadiness appear to have reached maxima in the 1760s and increased again, from lower values in the following decade, to the 1820s.These changes need to be further substantiated with the available log entries concerning winds, weather, and rates of progress. A similar fleshing out of fragmentary preinstrumental pre-standardized records with current climatic characteristics is suggested for the routes fanning out east of the Cape towards Arabia, India, China, Indonesia, and Australia.Climate Diagnostics Center, NOAAWith 5 Figures     

New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis

The Northwest Africa (NWA) 2996 meteorite is a lunar regolith breccia with a “mingled” bulk composition and slightly elevated incompatible element content. NWA 2996 is dominated by clasts of coarse‐grained noritic and troctolitic anorthosite containing calcic plagioclase (An#~98) and magnesian mafic minerals (Mg#~75), distinguishing it from Apollo ferroan anorthosites and magnesian‐suite rocks. This meteorite lacks basalt, and owes its mingled composition to a significant proportion of coarse‐grained mafic clasts. One group of mafic clasts has pyroxenes similar to anorthosites, but contains more sodic plagioclase (An#~94) distinguishing it as a separate lithology. Another group contains Mg‐rich, very low‐titanium pyroxenes, and could represent an intrusion parental to regional basalts. Other clasts include granophyric K‐feldspar, disaggregated phosphate‐bearing quartz monzodiorites, and alkali‐suite fragments (An#~65). These evolved lithics are a minor component, but contain minerals rich in incompatible elements. Several anorthosite clasts contain clusters of apatite, suggesting that the anorthosites either assimilated evolved rocks or were metasomatized by a liquid rich in incompatible elements. We used Lunar Prospector gamma‐ray spectrometer remote sensing data to show that NWA 2996 is most similar to regoliths in and around the South Pole Aitken (SPA) basin, peripheral regions of eastern mare, Nectaris, Crisium, and southern areas of Mare Humorum. However, the mineralogy of NWA 2996 is distinctive compared with Apollo and Luna mission samples, and is likely consistent with an origin near the SPA basin: anorthosite clasts could represent local crustal material, mafic clasts could represent intrusions beneath basalt flows, and apatite‐bearing rocks could carry the SPA KREEP signature.     

Evaluation of trace element contents in groundwater in Abakaliki metropolis and around the abandoned mine sites in the southern part, Southeastern Nigeria

This study aimed at determining the concentrations of trace elements in the groundwater of Abakaliki urban and some abandoned mine sites in the Southern part. Sixteen trace elements were analyzed for each of the twenty water samples collected. Laboratory results showed that the concentration of manganese varied from 4.816 to 11.238 ppm, zinc from 0.126 to 1.403 ppm, copper from 0.198 to 0.967 ppm, lead from 0.005 to 0.010 ppm, arsenic from 0.001 to 0.009 ppm, chromium from 0.009 to 0.025 mg/l, cadmium from 0.003 to 0.011 mg/l, mercury from 0.001 to 0.005 mg/l, nickel from 0.008 to 0.032 mg/l, selenium from 0.001 to 0.011 ppm, iodine from 0.013 to 0.050 ppm, uranium from 0.001 to 0.006 ppm, platinum from 0.009 to 0.032 ppm, tin from 0.014 to 0.015 ppm, lithium from 0.009 to 0.024 mg/l, cobalt from 0.015 to 0.036 mg/l, and iron from 0.010 to 0.980 ppm. These results were analyzed statistically and their distribution modeled using a software package. The results were also compared with world standards for potable water. The comparison showed that water samples are contaminated with trace elements and particularly polluted with, Mn, Hg, and Cd with average concentration values of 8.43, 0.002, and 0.005 mg/l, all above the World Health Organization standard limits of 0.005, 0.001 and 0.003 mg/l, respectively. Concentrations of Fe, Zn, and Ni are above the permissible limits of 0.30, 0.01, and 0.02 mg/l, respectively, in some places. Health hazards like metal poisoning which can result from pollution of this nature cannot be ruled out. Controlling processes such as chemical dissolutions, mechanical weathering and pollution from urban sewage, release the trace elements to the soil system while chemical dilution, otherwise called leaching, streamlines the trace element plumes to the groundwater regime with dispersion processes mixing and spreading the plume. Dispersion trends of the elements show point sources from the southern part, indicating presence of ore deposits, most likely sulfide ores as interpreted from correlation matrix.