WEEKLY CLIMATE NEWS

1-5 March 2010

TRMM WEB PRODUCTS HAVE RETURNED

Investigation 5A may be completed as directed in the Investigations Manual.

Report From the Field - Lucky Greenleaf, a DataStreme Ocean LIT Leader from Belfast, ME, reported that El Nino conditions, associated with anomalous large-scale atmospheric and ocean circulation patterns, produced unusual weather for February 2010 along the coast of Maine. He said that the region experienced rainy and windy conditoins, with very little snow. Nighttime temperatures ranged from 25 to 40 degrees F, while daytime temperatures were between 35 and 50 degrees. On Sunday (28 February), warm weather was found along the coast, with bare ground (no snow) and muddy or potholed roads.

ITEMS OF INTEREST

CURRENT CLIMATE MONITORING

CLIMATE FORCING

CLIMATE IMPACTS ON THE BIOSPHERE

CLIMATE FORECASTS

PALEOCLIMATE RECONSTRUCTION

CLIMATE AND SOCIETY

Concept of the Week: Keeping your cool!

In order to survive, humans need to maintain a nearly constant internal core temperature that is within several degrees of 98.6 degrees Fahrenheit. Your internal temperature depends upon an energy balance involving the gain and loss of energy from radiation (incoming solar versus incoming and outgoing infrared radiation), sensible heat transfer (conduction and convection), latent heat of evaporation (respiration and perspiration) and the body's metabolic rate. This heat transfer depends upon the differences between skin temperature and the ambient air temperature of the surroundings. In addition, wind and atmospheric humidity can affect the rate of sensible and latent heat transfer. Problems arise when either too much or too little heat flows to or from the body, yielding hypothermia and hyperthermia (heat stress) conditions, respectively.

When the air temperature increases, heat flow from the body is often reduced. Heat flow can be increased to maintain stable temperatures involuntarily by thermoregulatory processes such as increased perspiration (sweating) and dilation of the blood vessels. Humans can also act to prevent hyperthermia by selecting lightweight and light colored clothes, as well as seeking of shade and well ventilated locations. Unfortunately, high atmospheric humidity that often accompanies high summer temperatures also reduces body heat loss since evaporative cooling by perspiration is suppressed. During the summer, the National Weather Service alerts the public of potentially dangerous combinations of high air temperature and atmospheric humidity levels by calculating the Heat Index.

Statistics kept by the National Weather Service reveals that heat (along with high humidity) is responsible for the greatest number of weather-related deaths across the nation during the 10-year period (1998-2007), with 170 fatalities occurring per year. By comparison, 62 deaths per year are associated from tornadoes and 14 deaths annually caused by the cold (low temperatures). Furthermore, concern has been raised that during this century, more frequent and more severe heat waves due to global climate change could become more common, leading to a greater risk of hyperthermia and, ultimately, to higher morbidity rates.

Concept of the Week: Questions

(Each week you will be asked to respond to two questions relating to that week's Concept of the Week topic. Place your responses on the Chapter Progress Response Form provided in the Study Guide.)

  1. The heat index is a function of air temperature and [(atmospheric humidity),(wind speed),(sunshine levels)].
  2. The annual number of fatalities across the nation in the last ten years due to heat stress is approximately [(15), (60), (170)].

Historical Events:

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2010, The American Meteorological Society.