Need for Austere Arctic Capable Weather Sensors in Interior Alaska to Improve Aviation Safety and the Available Meteorological Sensing Network

The North American Arctic suffers from a harsh polar continental climate with extreme cold air temperatures in the winter, compared to the Scandinavian Arctic that has moderated temperatures due to warm Gulf Stream waters. These harsh living conditions lead to lower populations and a general lack of infrastructure/road networks through much of Alaska. Population centers North and West of the Fairbanks-Anchorage transportation corridor are generally not connected by roads or rail and rely on air and/or ocean transport. Due to the lack of infrastructure outside of the Fairbanks-Anchorage corridor the response to a significant emergency would require a defense support of civilian agency airlift using helicopter or cargo/transport planes. Such a response relies on weather models to forecast and identify any airborne safety hazards such as icing and low level wind shear. It also requires landing weather conditions for locations which may or may not be near an airport/town with a fixed meteorological sensor, often dependent on a connection to a local commercial power grid. For first in emergency operations a portable self-powered meteorological sensor capable of operating in the Arctic for 3-5 days without commercial/generator power would be ideal. Improvements in the density of fixed-location meteorological sensors would also vastly improve meteorological model forecasts for flight safety.

The lack of infrastructure and sparse population create major difficulties in setting up a robust meteorological observation network in Alaska. There are few sensors North or West of Fairbanks resulting in some interior regions having only one surface reporting meteorological data-point for a much larger area than would be typical for a sensing network in temperate climates. Commercial power required to operate most meteorological stations also creates a bias towards sensors being disproportionately located near population centers and transportation corridors typically built along rivers, flat/valley locations and lower elevation mountain passes. This results in an abundance of low elevation stations on relatively flat terrain with very little in-situ ground-truth meteorological/hydrological datum reported from higher elevations or rugged hill/mountain terrain. The density of the network could be improved by working with tribes and small settlements to place more sensors where there is a reliable source of power. However, to operate sensors in the undeveloped back-country, there would have to be improvements to self-powered weather stations which would allow sustained sensing through periods of cold and dark Arctic conditions.

Powering an off-grid meteorological/hydrological station in the Arctic comes with it’s own set of problems, unique from those of temperate and tropical/desert climates. Air temperatures from November – April often drop below the optimum operating temperatures for lead-sulfate, lithium ion, and sometimes nickel-cadmium batteries. This can lead to loss of charge or permanent damage to the battery. Due to the low sun angle and the shortness of days in high latitudes, including areas beyond the Arctic Circle that go days without a sunrise, the effectiveness of battery recharging through solar technologies would be reduced or eliminated through a significant period of the winter. Interior Alaska can have strong winter inversions with cold still air trapped in valleys. These conditions would impede the ability to charge sensor batteries using a wind turbine for up to weeks at a time. However, this lack of wind is less of an issue for hills and mountain passes. The low air temperature problem for batteries would require very good insolation to protect from the elements, while periods without a battery recharge option would require battery banks large enough to sustain operations through the period expected to have no solar/wind recharge capabilities. Finally there are other off grid options such as using a gas generator, but supplying the gas, or building a large tank to last through the winter would be a limiting factor for this option in remote areas.

Without considering maintenance, environmental, or economic feasibility, power appears to be a main limiting factor to improving surface based meteorological sensing in the Alaska Arctic/sub-arctic region. Many commercially available sensors work fine on or off grid in temperate and desert/tropical locations. However, factors such as lack of sunlight/wind and air temperatures dropping below battery operating minimums require modification to the current sensors or improvements in battery technology. Otherwise, new/upgraded sensors will need to be developed that operate with lower power/battery requirements, to offset the issue of available power.

Decreased power requirements of sensors would also have to be balanced against additional heat energy/power required to melt snow and ice off sensors if attempting to field without a regular (daily) maintenance person. Snow or thick frost/ice cover would affect instruments such as the cloud height detector, present weather detector, precipitation gauge, and sometimes the anemometer. The issues caused by snow or ice cover may also be solved through alternative instruments to measure the same weather elements, but are not currently part of a typical fielded weather system.

There is a safety/educational need for sensor options that can work off grid in the extreme cold conditions found in the Arctic winter months. This upgraded/new equipment would allow the possibility of a more robust and dense meteorological network in the Arctic. This could lead to better data ingested into weather forecast models or available for ground-truth model correction. It may also lead to portable stand-alone systems that can be temporarily placed at an emergency airlift site to improve aviation safety for first responders and long term aid missions.