The Meteorological Buoy and Coastal Marine Automated Network for the United States (1998) / Chapter Skim
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3 Applications of Buoy/C-MAN Data Network
3 Applications of Buoy/C-MAN Data Network
Pages 25-39
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From page 25... ...
C-MAN reporting stations also provide the first indication of the severe effects of ocean storms and hurricanes as they approach the coast based on changes in the reported wind direction and speed, temperature, and sea-level pressure. Forecasters must have knowledge of these often rapidly changing coastal weather conditions in order to provide timely and accurate warnings of high winds, storm surges, and coastal dOoding associated with tropical and extratropical storms (Meadows et al., 1997; Xie et al., 1997~.
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From page 26... ...
Buoys moored more than 250 km offshore can provide valuable early warning information on atmospheric and oceanic conditions associated with storms headed toward the coast. A combination of coastal Doppler radar precipitation, wind, and wave information; C-MAN observations near shore; moored buoy observations Tocated well offshore; and satellite imagery provide information for NWS forecasters to improve warning lead times associated with major storms approaching the coast.
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From page 27... ...
A coastal observation program would be shortsighted without an adaptive observation provision to deploy more drifting buoys to monitor environmental conditions in the various tropical storm regions of the Atlantic Ocean and Gulf of Mexico and to increase the number of moored buoys in the Caribbean and GulfofMexico. In addition to enhancing warnings for the United States, Puerto Rico, and the virgin Islands, the buoy data (moored and drifters)
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From page 28... ...
Examples abound, such as the formation of atmospheric and oceanic fronts, modification of the surface wind field, seastate generation, hurricane track and intensity, ocean response to intense atmospheric forcing, radiation fog, mid latitude extra tropical cyclones (ETCs) genesis and coastal and estuarine storm surge, to name a few.
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From page 29... ...
Studies related to hurricane forecasts near landfall include quantification of mechanisms associated with rapid intensity change and initialization of dynamical hurricane models with coastal radar, satellite, and at sea in situ data. Studies also include efforts to provide current analysis of storm intensity and track from satellite and radar data, to explore adaptive observing strategies for forecasts within and beyond two days, to understand the effects of coastlines and coastal mountains, and to determine the mechanisms that underlie the occurrence of localized extreme winds, rainfall, tornadoes, storm surge, and fresh water nooding.
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From page 30... ...
to fully capture all the important finescaTe details of the mid-Atlantic coastal barocTinic zone, which during winter months is often typified by SST and air temperature gradients on the order of 10-15°C over 5-10 km within the vicinity of the Gulf Stream SST frontal zone. It is this understandable yet still problematic distinction between the averaged and highly smoothed surface data used in today's operational weather forecast models and the actual mid-Atlantic coastal zone surface conditions that most likely gives the impression that coastal cyclone intensification is not usually well represented in numerical weather prediction models.
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From page 31... ...
Models will be more capable of assimilating relevant information related to a convectively disturbed initial state.
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From page 32... ...
The forecast deficiencies are similar to that of winter storms. An important distinction for coastal storms is that the principal hazards are often rain and wind related, as in the "nor'easters" of the east coast or the "pineapple express" storms ofthe west coast.
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From page 33... ...
These NOAA reports have consistently recommended that the coastal and offshore data network over the Gulf of Mexico and the Atlantic and Pacific Oceans be expanded to allow for improved prediction and warning of explosive cyclogenesis and landfalling hurricanes. A synopsis of the relevant findings and recommendations on coastal and marine observations from recent NOAA Natural Disaster Survey Reports is found in Appendix E
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From page 34... ...
..~ _ _ _ FIGURE 14 Monthly number of Internet visits ("hits") for 1997 to the official web sites of the National Data Buoy Center (NDBC)
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From page 35... ...
VOLUNTEER OBSERVING SHIPS Two platforms that are particularly useful in obtaining observations over much of the world's oceans are satellites in space and commercial and other volunteer ships of opportunity at sea. Ship reports are concentrated along the major global trade routes and are provided at internationally agreed upon synoptic times, typically four or eight times per day (and sometimes more frequently near major oceanic cyclones and hurricanes)
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From page 36... ...
Model forecasts of wind, temperature, significant wave heights, relative humidity, and precipitation, among other variables, along with derived statistical-dynamical guidance products from these models, are examined by operational meteorologists at various NWS offices across the United States several times daily. Forecasters charged with the responsibility for preparing forecasts and issuing warnings to the general public, interested federal, state and local agencies, and public safety officials scrutinize and interpret the mode!
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From page 37... ...
In the atmosphere, there is little information about boundary layer structure, especially in the divergent trade cumulus regions, which tend to lie in oceanic regions without upper air observations. Since the ability of models to simulate and assimilate near surface data depend on boundary layer processes, this is a serious gap which again is best addressed by both satellite, coastal radar, drifter and marine buoy and C-MAN data.
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From page 38... ...
These buoy data and ship reports are more suitable for estimating wind stress, with satellite data used to fig in spatial voids. in general, advanced satellite remote wind sensors such as radar scatterometers, radar altimeters, and passive microwave sensors, lack the sensitivity to resolve winds above about 20 m so, which means that remote sensors are able to resolve the intensity of extra tropical cyclones (ETCs)
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From page 39... ...
However, only a small fraction of the VOS Beet operates XBTs and the data in fact are inadequate to generate monthly maps of upper-ocean thermal structure, and only bimonthly maps can be constructed. In the context of seasonal to interannual prediction, sea-level observations are useful as an integral constraint on model initialization fields and as a mode!
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