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31.
Daqing Yang Barry E. Goodison John R. Metcalfe Valentin S. Golubev Esko Elomaa Thilo Gunther Roy Bates Timothy Pangburn Clayton L. Hanson Douglas Emerson Voilete Copaciu Janja Milkovic 《水文研究》1995,9(8):877-895
The Tretyakov non-recording precipitation gauge has been used historically as the official precipitation measurement instrument in the Russian (formerly the USSR) climatic and hydrological station network and in a number of other European countries. From 1986 to 1993, the accuracy and performance of this gauge were evaluated during the WMO Solid Precipitation Measurement Intercomparison at 11 stations in Canada, the USA, Russia, Germany, Finland, Romania and Croatia. The double fence intercomparison reference (DFIR) was the reference standard used at all the Intercomparison stations in the Intercomparison. The Intercomparison data collected at the different sites are compatible with respect to the catch ratio (measured/DFIR) for the same gauge, when compared using mean wind speed at the height of the gauge orifice during the observation period. The Intercomparison data for the Tretyakov gauge were compiled from measurements made at these WMO intercomparison sites. These data represent a variety of climates, terrains and exposures. The effects of environmental factors, such as wind speed, wind direction, type of precipitation and temperature, on gauge catch ratios were investigated. Wind speed was found to be the most important factor determining the gauge catch and air temperature had a secondary effect when precipitation was classified into snow, mixed and rain. The results of the analysis of gauge catch ratio versus wind speed and temperature on a daily time step are presented for various types of precipitation. Independent checks of the correction equations against the DFIR have been conducted at those Intercomparison stations and a good agreement (difference less than 10%) has been obtained. The use of such adjustment procedures should significantly improve the accuracy and homogeneity of gauge-measured precipitation data over large regions of the former USSR and central Europe. 相似文献
32.
《Marine Policy》2016
New Zealand's Quota Management System (QMS) consists of a two tier operational structure: Quota shares in a fishstock provide an Annual Catch Entitlement (ACE) of the total allowable commercial catch (TACC) of the specific fishstock. Fishers operating in a multispecies fishery need a portfolio of ACE that matches the mix of their annual catch. Fishers may own quota shares, and thereby receive the needed ACE allocations or they may operate without quota shares and rely on acquiring ACE in the ACE market. Whatever the fisher's situation, it is common for fishers to both buy and sell ACE during a fishing year as they seek to balance their actual catch against ACE. The incentive to achieve a balance is strong because at year-end fishers whose catch exceeds ACE are required to pay a fee called ‘deemed value’. For many fishstocks the deemed value fee increases sharply as the percentage by which a fisher's catch exceeds their ACE increases. When no ‘unbalanced’ ACE is available for purchase, an overfished fisher may attempt to mitigate their deemed value liability by engaging in arbitrage trading in ACE whereby they buy ACE from other overfished fishers. This study examines the nature and extent of ACE arbitrage behaviour in the New Zealand quota managed fishery. The study finds that the number of fishstocks where arbitrage trading occurs is relatively small and is declining. However, sizeable deemed value mitigation transactions are still evident. 相似文献
33.
Limiting accessibility to a fishing area can reduce fishing effort effectively and may therefore promote local recovery of depleted stocks. In January 2002, beach driving was banned in South Africa, thereby reducing angler access to large areas of the coastline, particularly in less-developed areas. In November 2001 a project had been established in the St Lucia Marine Reserve, on the east coast of South Africa, to compare surf-zone fish populations inside a no-take sanctuary zone with those in an adjacent exploited area. Subsequent to the ban, the aim of the project was adapted such that surf-zone fish populations were monitored for potential recovery in what had been the exploited area, located to the north of Cape Vidal, which anglers could no longer access easily, because of the prohibition on beach driving. Standardised research fishing was conducted at two sites in the previously exploited area and two sites in the no-take sanctuary. Conventional stock-status indicators showed evidence of recovery in the four most common species caught in the previously exploited area, in terms of both abundance and biomass. Generalised additive mixed models were used to account for the influence of targeting specific species; however, subtle differences in habitat between the sampling sites, improved angling skill over time, variability in recruitment, and differential species-specific responses complicated interpretation of results. The implications of the findings are discussed in terms of the future monitoring and management of marine protected areas both within the St Lucia Marine Reserve and farther afield. 相似文献
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