Forecasters Handbook for the Bering Sea, Aleutian Islands, and Gulf of Alaska

Fett, Robert W.; Englebretson, Ronald E; Perryman, D. C.

doi:10.21236/ada268344

Cited by 19 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While radiosondes can accurately detect CAA at a specific point in time and space, they are limited in their ability to characterize the spatial extent of CAA events and their launches may not always take place for reasons such as staffing shortage, equipment malfunction, or network outages. While some sites like Anchorage (ANC) have higher launch counts (N = 101, including both 00 UTC and 12 UTC), radiosondes from remote sites like Shemya Island (SYA) can be affected by frost formation upon passing through stratus clouds which cause balloons to burst at lower altitudes (N = 71) [14]. CAA can also be detected using AMDAR data, which is a collection of measured and derived meteorological parameters (including air temperature) from aircraft sensors.…”

Section: Methodsmentioning

confidence: 99%

Evaluating Satellite Sounding Temperature Observations for Cold Air Aloft Detection

et al. 2020

View full text Add to dashboard Cite

Cold Air Aloft (CAA) can impact commercial flights when cold air descends below 12,192 m (40,000 ft) and temperatures drop dramatically. A CAA event is identified when air temperature falls below −65 °C, which decreases fuel efficiency and poses a safety hazard. This manuscript assesses the performance of the National Oceanic and Atmospheric Administration Unique Combined Atmospheric Processing System (NUCAPS) in detecting CAA events using sounders on polar-orbiting satellites. We compare NUCAPS air temperature profiles with those from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) for January–March 2018. Of 1311 collocated profiles, 236 detected CAA. Our results showed that NUCAPS correctly detects CAA in 48.1% of profiles, while 17.2% are false positives and 34.7% are false negatives. To identify the reason for these detection states, we used a logistic regression trained on NUCAPS diagnostic parameters. We found that cloud cover can impact the skill even at higher vertical levels. This work indicates that a CAA-specific quality flag is feasible and may be useful to help forecasters to diagnose NUCAPS in real-time. Furthermore, the inclusion of an additional sounder data source (e.g., NOAA-20) may increase CAA forecast accuracy. Cloud scenes change rapidly, so additional observations provide more opportunities for correct detection.

show abstract

Section: Methodsmentioning

confidence: 99%

Evaluating Satellite Sounding Temperature Observations for Cold Air Aloft Detection

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Consequently, harbor seals have greater flexibility in the haul-out locations that they choose, which may include isolated habitats as well as the shorelines of large islands due to the lack of predation risk there. Second, the tidal range (i.e., difference in height between low and high tide) is roughly 2-5 times smaller in the Aleutian Islands compared with the Gulf of Alaska or Bristol Bay in mainland Alaska (Fett et al 1993), and therefore, has much less impact on haul-out habitat availability in the intertidal zone. Analysis of haul-out behavior from biologgers recently deployed on harbor seals in the Aleutian Islands seems to support this with a relatively flat response to time from low tide (AFSC, unpublished data).…”

Section: Tidementioning

confidence: 99%

Evaluating the use of thermal imagery to count harbor seals in aerial surveys

et al. 2022

View full text Add to dashboard Cite

Aerial surveys of pinnipeds are often used to estimate abundance, a critical component of stock assessments and management decisions. In Alaska, USA, aerial surveys of harbor seals (Phoca vitulina) have historically relied on visual detections by human observers, a method which works well on large groups of seals at predictable haul-out locations, or when seals are located on a visually uniform substrate such as a sandy beach or exposed mudflat. However, regions such as the Aleutian Islands of Alaska, where harbor seals haul out in small numbers at variable locations and are inconspicuous on shore, are challenging to survey accurately. To determine whether the use of thermal imaging techniques would improve detections of harbor seals in the Aleutian Islands, we conducted a study to compare counts derived from visual detections documented by color photographs with those derived from thermal detections documented by infrared images. In 2019, we conducted 15 flights in the Aleutian Islands, completing 129 experimental trials. We manually reviewed color and thermal images to count harbor seals and used a Bayesian analysis to explore the effects of several covariates on seal detections. The thermal method detected more harbor seals than the visual method early in the day, when cloud cover was greater, and when observers had more experience operating the thermal imaging equipment. The relative improvement in performance of the thermal method was particularly notable when surveys occurred four or more hours prior to solar noon. We discuss the costs and benefits of incorporating thermal technology as part of the existing monitoring program for harbor seals in the Aleutian Islands, including the need to control for differences if incorporating new survey methods based on thermal detection.

show abstract

“…2 this phenomenon is dangerous for big ships in specific conditions too. J. E. Overland [20], R. W. Fett and T. L. Kozo [9] and R. W. Fett et al [8] describe a tragic example of the effects of sea spray icing.…”

Section: Characteristics Of Icing Phenomenonmentioning

confidence: 99%

Phenomenon of Icing and a Review of Ice Accretion Nomograms, Models and Charts in Navigation

Dyrcz

2019

Scientific Journal of Polish Naval Academy

View full text Add to dashboard Cite

The paper presents results of research based on analysis of marine icing nomograms, models and charts using in the sea navigation. The problem of ships icing occurs in specific weather and geographical conditions. Every year numbers of vessels navigate in these areas meet a phenomenon of icing. Ice on decks of ships can be formed from fresh water or sea (salt) water. Ships operating in waters where the phenomime of icing is occurred use for safety navigation icing nomograms and icing charts. Icing charts are created based on icing models. The main aim of the article is to perform a review of currently used in the sea navigation icing nomograms and icing maps, based on icing models, used in navigation to depict the phenomenon of icing.

show abstract

Forecasters Handbook for the Bering Sea, Aleutian Islands, and Gulf of Alaska

Cited by 19 publications

References 9 publications

Evaluating Satellite Sounding Temperature Observations for Cold Air Aloft Detection

Evaluating Satellite Sounding Temperature Observations for Cold Air Aloft Detection

Evaluating the use of thermal imagery to count harbor seals in aerial surveys

Phenomenon of Icing and a Review of Ice Accretion Nomograms, Models and Charts in Navigation

Contact Info

Product

Resources

About