4MOST: the 4-metre Multi-Object Spectroscopic Telescope project status: instrument manufacturing and integration, operations development, and survey planning

Author(s):  
Roelof S. de Jong ◽  
Samual C. Barden ◽  
Olga Bellido-Tirado ◽  
Joar G. Brynnel ◽  
Isabella Cesarini ◽  
...  
Keyword(s):  
2021 ◽  
pp. 1-13
Author(s):  
Jing Duan ◽  
Xiaoxia Wan ◽  
Jianan Luo

Abstract Due to the vast ocean area and limited human and material resources, hydrographic survey must be carried out in a selective and well-planned way. Therefore, scientific planning of hydrographic surveys to ensure the effectiveness of navigational charts has become an urgent issue to be addressed by the hydrographic office of each coastal state. In this study, a reasonable calculation model of hydrographic survey cycle is established, which can be used to make the plan of navigational chart updating. The paper takes 493 navigational charts of Chinese coastal ports and fairways as the research object, analyses the fundamental factors affecting the hydrographic survey cycle and gives them weights, proposes to use the BP neural network to construct the relationship between the cycle and the impact factors, and finally establishes a calculation model of the hydrographic survey cycle. It has been verified that the calculation cycle of the model is effective, and it can provide reference for hydrographic survey planning and chart updating, as well as suggestions for navigation safety.


<em>Abstract</em>.—Hurricanes Katrina and Rita critically impacted the northern Gulf Coast. Shrimping and other commercial fishing industries saw large scale destruction of vessels and shore based facilities in addition to a deposition of large amounts of debris on fishing grounds from Alabama to Louisiana. In 2006, the National Oceanic and Atmospheric Administration’s (NOAA’s) Office of Coast Survey and Office of Response and Restoration started the implementation of a large scale hazards survey program to map the coastal waters of Louisiana, Mississippi, and Alabama. The first phase of the effort involved surveying more than 600 square nautical miles of coastal bays and nearshore waters with sidescan and single beam acoustic sonar. Survey findings are posted each week on a NOAA public Web site displaying the location of each hazard and debris found. The survey work is also updating the NOAA navigation charts for coastal areas that are used heavily by fishing vessels, the navigation industry, and recreational boaters. Survey planning and implementation is conducted cooperatively with the marine fisheries agencies of Alabama, Mississippi, and Louisiana.


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