Gary L. Hufford

CROSSING THE ULTIMATE ECOLOGICAL BARRIER: EVIDENCE FOR AN 11 000-KM-LONG NONSTOP FLIGHT FROM ALASKA TO NEW ZEALAND AND EASTERN AUSTRALIA BY BAR-TAILED GODWITS

Abstract Populations of the Bar-tailed Godwit (Limosa lapponica; Scolopacidae) embark on some of the longest migrations known among birds. The baueri race breeds in western Alaska and spends the nonbreeding season a hemisphere away in New Zealand and eastern Australia; the menzbieri race breeds in Siberia and migrates to western and northern Australia. Although the Siberian birds are known to follow the coast of Asia during both migrations, the southern pathway followed by the Alaska breeders has remained unknown. Two questions have particular ecological importance: (1) do Alaska godwits migrate directly across the Pacific, a distance of 11 000 km? and (2) are they capable of doing this in a single flight without stopping to rest or refuel? We explored six lines of evidence to answer these questions. The distribution of resightings of marked birds of the baueri and menzbieri races was significantly different between northward and southward flights with virtually no marked baueri resighted along the Asian mainland during southward migration. The timing of southward migration of the two races further indicates the absence of a coastal Asia route by baueri with peak passage of godwits in general occurring there a month prior to the departure of most birds from Alaska. The use of a direct route across the Pacific is also supported by significantly more records of godwits reported from within a direct migration corridor than elsewhere in Oceania, and during the September to November period than at other times of the year. The annual but rare occurrence of Hudsonian Godwits (L. haemastica) in New Zealand and the absence of their records along the Asian mainland also support a direct flight and are best explained by Hudsonian Godwits accompanying Bar-tailed Godwits from known communal staging areas in Alaska. Flight simulation models, extreme fat loads, and the apparent evolution of a wind-selected migration from Alaska further support a direct, nonstop flight. Atravesando la Barrera Ecológica Final: Evidencia de un Vuelo sin Escala de 11 000 km de Longitud desde Alaska a Nueva Zelanda y el Este de Australia por Limosa lapponica Resumen. Las poblaciones de Limosa lapponica (Scolopacidae) se embarcan en una de las migraciones más largas conocidas para aves. La raza baueri cría en el oeste de Alaska y pasa la estación no reproductiva a un hemisferio de distancia en Nueva Zelanda y el este de Australia; la raza menzbieri cría en Siberia y migra hacia el oeste y el norte de Australia. Aunque se sabe que las aves de Siberia siguen la costa de Asia durante ambas migraciones, la ruta meridional que siguen las aves reproductivas de Alaska ha permanecido desconocida. Dos preguntas tienen particular importancia ecológica: (1) ¿las aves de Alaska migran directamente a través de Pacífico, a lo largo de 11 000 km? y (2) ¿son capaces de hacerlo en un único vuelo sin parar a descansar y reabastecerse? Exploramos seis líneas de evidencia para responder a estas preguntas. La distribución de avistamientos de aves marcadas de las razas baueri y menzbieri fue significativamente diferente entre vuelos hacia el norte y el sur, sin que hubiera prácticamente un solo avistamiento de individuos marcados de baueri a lo largo del continente asiático durante la migración hacia el sur. El período de la migración hacia el sur de ambas razas indica la ausencia de una ruta costera asiática para baueri, con un pico en el paso de las aves ocurriendo allí un mes antes de la partida de la mayoría de las aves desde Alaska. El uso de una ruta directa a través del Pacífico también está avalado por un número significativamente mayor de aves reportadas para un corredor migratorio directo que para cualquier otro lugar de Oceanía, y para el período entre septiembre y noviembre que para otros momentos del año. La presencia anual, aunque rara, de L. haemastica en Nueva Zelanda y la ausencia de registros a lo largo del continente asiático también avalan la posibilidad de un vuelo directo y se explican mejor por el hecho de que L. haemastica acompaña a L. lapponica desde áreas de escala comunes en Alaska. Evidencia complementaria de un vuelo directo sin escalas está dada por modelos de simulación de vuelo, la gran acumulación de grasa en las aves y la aparente evolución de una migración seleccionada por el viento.

El Niño and its impact on fire weather conditions in Alaska

Examining the relationship of El Nino to weather patterns in Alaska shows wide climate variances that depend on the teleconnection between the tropics and the northern latitudes. However, the weather patterns exhibited in Alaska during and just after moderate to strong El Nino episodes are generally consistent: above normal temperature and precipitation along the Alaskan coast, and above normal temperature and below normal precipitation in the interior, especially through the winter. The warm, dry conditions in the Alaskan interior increase summer wildfire potential. Statistics on the area burned since 1940 show that 15 out of 17 of the biggest fire years occurred during a moderate to strong El Nino episode. These 15 years account for nearly 63% of the total area burned over the last 58 years. Evidence points to increased dry thunderstorms and associated lightning activity during an El Nino episode; the percentage of total area burned by lightning caused fires during five episodes increased from a normal of less than 40% to a high of about 96%.

The February 2001 Eruption of Mount Cleveland, Alaska: Case Study of an Aviation Hazard

Mount Cleveland, Alaska (528499N, 1698579W), located on Chuginadak Island, erupted on 19 February 2001. The atmosphere‐volcanic plume interactions that occurred as part of this event led to several serious encounters of commercial aircraft with the ash. A number of continental and oceanic air traffic control areas were affected. Here, a detailed case study of the eruption, subsequent movement of the airborne plume, and operational response is presented. The likelihood of such encounters in the future may be reduced as a result of lessons learned from this event. Some potential new assets for improving the detection of and response to the airborne volcanic ash hazard to aviation also are discussed.

Hemispheric-scale wind selection facilitates bar-tailed godwit circum-migration of the Pacific

The annual 29 000 km long migration of the bar-tailed godwit, Limosa lapponica baueri, around the Pacific Ocean traverses what is arguably the most complex and seasonally structured atmospheric setting on Earth. Faced with marked variation in wind regimes and storm conditions across oceanic migration corridors, individuals must make critical decisions about when and where to fly during nonstop flights of a weeks duration or longer. At a minimum, their decisions will affect wind profitability and thus reduce energetic costs of migration; in the extreme, poor decisions or unpredictable weather events will risk survival. We used satellite telemetry to track the annual migration of 24 bar-tailed godwits and analysed their flight performance relative to wind conditions during three major migration legs between nonbreeding grounds in New Zealand and breeding grounds in Alaska. Because flight altitudes of birds en route were unknown, we modelled flight efficiency at six geopotential heights across each migratory segment. Birds selected departure dates when atmospheric conditions conferred the greatest wind assistance both at departure and throughout their flights. This behaviour suggests that there exists a cognitive mechanism, heretofore unknown among migratory birds, that allows godwits to assess changes in weather conditions that are linked (i.e. teleconnected) across widely separated atmospheric regions. Godwits also showed adaptive flexibility in their response not only to cues related to seasonal changes in macrometeorology, such as spatial shifting of storm tracks and temporal periods of cyclogenesis, but also to cues associated with stochastic events, especially at departure sites. Godwits showed limits to their response behaviours, however, especially relative to rapidly developing stochastic events while en route. We found that flight efficiency depended significantly upon altitude and hypothesize that godwits exhibit further adaptive flexibility by varying flight altitude en route to optimize flight efficiency. The Association for the Study of Animal Behaviour. Published by Elsevier Ltd.

Long-term climate patterns in Alaskan surface temperature and precipitation and their biological consequences

Mean monthly climate maps of Alaskan surface temperature and precipitation produced by the parameter-elevation regression on independent slopes model (PRISM) were analyzed. Alaska is divided into interior and coastal zones with consistent but different climatic variability separated by a transition region; it has maximum interannual variability but low long-term mean variability. Pacific decadal oscillation (PDO)- and El Nino Southern Oscillation (ENSO)-type events influence Alaska surface temperatures weakly (1-2/spl deg/C) statewide. PDO has a stronger influence than ENSO on precipitation but its influence is largely localized to coastal central Alaska. The strongest influence of Arctic oscillation (AO) occurs in northern and interior Alaskan precipitation. Four major ecosystems are defined. A major eco-transition zone occurs between the interior boreal forest and the coastal rainforest. Variability in insolation, surface temperature, precipitation, continentality, and seasonal changes in storm track direction explain the mapped ecosystems. Lack of westward expansion of the interior boreal forest into the western shrub tundra is influenced by the coastal marine boundary layer (enhanced cloud cover, reduced insolation, cooler surface and soil temperatures).

Resuspension of Relic Volcanic Ash and Dust from Katmai: Still an Aviation Hazard

Abstract Northwest winds were strong enough to continuously resuspend relic volcanic ash from the Katmai volcano cluster and the Valley of Ten Thousand Smokes on 20–21 September 2003. The ash cloud reached over 1600 m and extended over 230 km into the Gulf of Alaska. Several factors influenced the resuspension of the ash: 1) the atmosphere and land surface were very dry prior to the event, further enabling the resuspension and subsequent atmospheric transport of the relic volcanic ash; 2) the production of winds strong enough to entrain and lift the ash over 1600 m into the atmosphere; 3) the complex terrain with numerous mountains interspersed with valleys, channels, and gaps; 4) the superadiabatic lapse rate for the troposphere below 850 mb; and 5) the presence of a strong subsidence inversion around 1400–1600 m. The authors propose that the strong winds are due to accelerations in a superadiabatic atmosphere below 850 mb that is buoyant to both upward and downward perturbations resulting in a hydraulic...

Hydrologic Scales, Cloud Variability, Remote Sensing, and Models: Implications for Forecasting Snowmelt and Streamflow

Accurate prediction of available water supply from snowmelt is needed if the myriad of human, environmental, agricultural, and industrial demands for water are to be satisfied, especially given legislatively imposed conditions on its allocation. Robust retrievals of hydrologic basin model variables (e.g., insolation or areal extent of snow cover) provide several advantages over the current operational use of either point measurements or parameterizations to help to meet this requirement. Insolation can be provided at hourly time scales (or better if needed during rapid melt events associated with flooding) and at 1-km spatial resolution. These satellite-based retrievals incorporate the effects of highly variable (both in space and time) and unpredictable cloud cover on estimates of insolation. The insolation estimates are further adjusted for the effects of basin topography using a high-resolution digital elevation model prior to model input. Simulations of two Sierra Nevada rivers in the snowmelt seasons of 1998 and 1999 indicate that even the simplest improvements in modeled insolation can improve snowmelt simulations, with 10%-20% reductions in root-mean-square errors. Direct retrieval of the areal extent of snow cover may mitigate the need to rely entirely on internal calculations of this variable, a reliance that can yield large errors that are difficult to correct until long after the season is complete and that often leads to persistent underestimates or overestimates of the volumes of the water to operational reservoirs. Agencies responsible for accurately predicting available water resources from the melt of snowpack [e.g., both federal (the National Weather Service River Forecast Centers) and state (the California Department of Water Resources)] can benefit by incorporating concepts developed herein into their operational forecasting procedures.

Using Spaceborne Synthetic Aperture Radar to Improve Marine Surface Analyses

Abstract The ever-changing weather and lack of in situ data in the Bering Sea warrants experimentation with new meteorological observing systems for this region. Spaceborne synthetic aperture radar (SAR) is well suited for observing the sea surface footprints of marine meteorological phenomena because its radiation is sensitive to centimeter-scale sea surface roughness, regardless of the time of day or cloud conditions. The near-surface wind field generates this sea surface roughness. Therefore, the sea surface footprints of meteorological phenomena are often revealed by SAR imagery when the main modulator of sea surface roughness is the wind. These attributes, in addition to the relatively high resolution of SAR products, make this instrument an excellent candidate for filling the meteorological observing needs over the Bering Sea. This study demonstrates the potential usefulness of SAR for observing Bering Sea meteorology by focusing on its ability to image the sea surface footprints of polar mesoscale ...

Use of Real-Time Multisatellite and Radar Data to Support Forest Fire Management

Abstract Combined digital data from multiple satellites and Doppler radar can provide fire weather meteorologists and resource managers with accurate information on forest fire location, intensity, growth, smoke plumes, and associated mesoscale weather. An integrated application using real-time satellite and radar is described for the Miller’s Reach forest fire that occurred in south-central Alaska in June 1996. Generated data and products were made available immediately on-scene via point-to-point high-speed portable satellite communications. This fire consumed over 15 000 ha and destroyed 344 structures.

Improved cloud detection in AVHRR daytime and night-time scenes over the ocean

Accurate cloud detection is a requirement of many geophysical applications that use visible and infrared satellite data (e.g. cloud climatologies, multichannel sea surface temperature (MCSST)). Unfortunately, a significant source of residual error in such satellite-based products is undetected cloud. Here, a new, computationally efficient cloud detection procedure for both daytime and night-time Advanced Very High Resolution Radiometer (AVHRR) data is developed. It differs substantially from our prior related work. First, a new clustering procedure is used, which produces more homogeneous and distinct clusters than those produced by either our previous work or the ISODATA algorithm of Ball and Hall. Second, the input information vector is reduced in size, incorporates both radiance and spatial components and each component is normalized. These changes improve the clustering/subsequent classification, tend to decrease execution time, and simplify post-processing of the classified (cloud, clear ocean) data ...