ABSTRACT. A survey of icebergs using satell ite radar images has been made in the seasonal sea-ice zone of East Antarctica in the sector between longitudes 50° and 145° E. These data provide information on the spatial distribution and size statistics of icebergs near the coast in areas not often visited by shipboard observers, and close to their sources at ice shelves and glacier tongues. The icebergs are detected and their dimensions extracted by analysis of the texture properties present in satellite images acquired with ERS-l synthetic aperture radar during the austral winter. The minimum size of iceberg reliably detected and measured is 0.06 km 2 .A significant variation, by up to a factor of two, is found in the area of icebergs close to different sections of the coast, which suggests a characteristic size for different sources. The average value of the length-to-width ratio for icebergs in the whole population shows some variability with size. The probability of finding icebergs is greatest close to the coast, decreasing in general with distance from the coast, such that few icebergs were detected more than 160 km from the coast. In one sector about 85° E, icebergs are found to at least 550 km from the coast, which is consistent with the transport of icebergs northwards in this region by a branch of the westward-heading near-coastal current (East Wind Drift ) which connects with the southern margins of the eastward-heading Antarctic Circumpolar Current.
Soil information is vital for a range of purposes; however, soils vary greatly over short distances, making accurate soil data difficult to obtain. Soil surveys were first carried out in the 1920s, and the first national soil map was produced in 1940. Several regional studies were done in the 1960s, with the national Land Type Survey completed in 2002. Subsequently, the transfer of soil data to digital format has allowed a wide range of interpretations, but many data are still not freely available as they are held by a number of different bodies. The need for soil data is rapidly expanding to a range of fields, including health, food security, hydrological modelling and climate change. Fortunately, advances have been made in fields such as digital soil mapping, which enables the soil surveyors to address the need. The South African Soil Science fraternity will have to adapt to the changing environment in order to comply with the growing demands for data. At a recent Soil Information Workshop, soil scientists from government, academia and industry met to concentrate efforts in meeting the current and future soil data needs. The priorities identified included: interdisciplinary collaboration; expansion of the current national soil database with advanced data acquisition, manipulation, interpretation and countrywide dissemination facilities; and policy and human capital development in newly emerging soil science and environmental fields. It is hoped that soil information can play a critical role in the establishment of a national Natural Agricultural Information System.
Abstract:We present an overview of key aspects of the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) data quality assurance program. Processes described include instrument deployment and calibration; instrument and facility maintenance; data collection and processing infrastructure; data stream inspection and assessment; problem reporting, review and resolution; data archival, display and distribution; data stream reprocessing; engineering and operations management; and the roles of value-added data processing and targeted field campaigns in specifying data quality and characterizing field measurements. The paper also includes a discussion of recent directions in ACRF data quality assurance. A comprehensive, end-to-end data quality assurance program is essential for producing a high-quality data set from measurements made by automated weather and climate networks. The processes developed during the ARM Program offer a possible framework for use by other instrumentation-and geographically-diverse data collection networks and highlight the myriad aspects that go into producing research-quality data.
Ground-based microwave radiometers (MWR) are becoming more and more common for remotely sensing the atmospheric temperature and humidity profile, as well as path integrated cloud liquid water content. The calibration accuracy of the state-of-the-art MWR HATPRO-G2 (Humidity And Temperature Profiler – Generation 2) was investigated during the second phase of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) in Northern Chile (5320 m a.m.s.l. – above mean sea level, 530 hPa) conducted by the the Atmospheric Radiation Measurement (ARM) program conducted between August and October 2009. This study assesses the quality of the two frequently used liquid nitrogen and tipping curve calibrations by performing a detailed error propagation study by exploiting the unique atmospheric conditions of RHUBC-II. Both methods are known to have open issues concerning systematic offsets and calibration repeatability. For the tipping curve calibration an uncertainty of 0.2–0.4 K (K-band) and 1.0–1.2 K (V-band) is found. The uncertainty in the tipping curve calibration is mainly due the atmospheric inhomogeneities. For the liquid nitrogen calibration the estimated uncertainty of 0.5–0.9 K is dominated by the uncertainty of the reflectivity of the liquid nitrogen target. Systematic offsets, which may cause the disagreement of both methods within their estimated uncertainties, are discussed
This paper reviews measures of manufacturing excellence and presents a design-formanufacturability (DFM) program organized around early design and manufacturing teamwork and the economic analysis of design options. Typical measures of manufacturing excellence for a semiconductor fabricator are expressed in terms of either operational or economic results. Those expressed in terms of operational results are independent of the product mix in the fabricator while those expressed in terms of economic results integrate both fabricator and product design attributes into a single parameter like revenue/wafer. Improvements in the operational measures of manufacturing excellence focus upon increases in capacity and throughput, defect density reductions, and cost containment. Improvements in the economic measures of manufacturing excellence must focus on both fabricator processing efficiency and the productivity of the design. Design-for-manufacturability practices can improve design productivity, time-tomarket, and product performance and reliability by closely coupling semiconductor fabrication knowledge with product requirements during the initial phase of a product design. Every design decision produces both technical and economic consequences; understanding these consequences and using this knowledge in the design process to optimize product productivity and profitability is key to achieving manufacturing excellence for that product.
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