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The El Niño-Southern Oscillation, the periodic “sloshing” back and forth of warm water between the eastern and western tropical Pacific, is believed to affect the frequency of tropical cyclone development in the North Atlantic. Specifically, during La Niña phases (when the waters off the west coast of South America are unusually cool) circulation in the [...]

The oceans and the atmosphere are constantly moving heat from the lower latitudes towards the poles. As the seasons change and one hemisphere gains more heat than the other, the intertropical convergence zone (ITCZ), or the area where the Northern Hemisphere’s easterly trade winds converge with the Southern Hemisphere’s, moves towards the warmer hemisphere, resulting [...]

About 40 percent of Australia’s agricultural production happens in the Murray River Basin, located in the southeastern corner of the world’s most arid developed continent. Annual rainfall in the region is highly variable and the period since 2001 has featured the lowest inflows into the Murray River on record. While the link between the El [...]

British Columbia’s Garibaldi Provincial Park, which lies about 70 miles north of Vancouver, features glacier-capped mountains as high as 9,500 feet. These glaciers have been retreating since the 1850′s, a decade generally recognized as the end of the “Little Ice Age,” a 200 year-long period that was relatively cool compared to the rest of the [...]

From about 800 to 1300 AD, much of the extra-tropical northern Hemisphere was relatively warm. This was especially true for northern Europe, which was dominated by warm and wet winters. This period has been called the Medieval Climate Anomaly (MCA). While the exact magnitudes of the warmth during this period are uncertain, it appears that [...]

The El Niño-Southern Oscillation (ENSO), a periodic (two to seven year) shifting of tropical Pacific sea surface temperatures (SSTs), is probably the best known source of multiannual variability in Earth’s climate. Shifting SSTs cause changes in upper-atmospheric circulation, which in turn changes temperature and rainfall levels at various locations throughout the world. Such temperature and [...]

Increases in water vapor in the stratosphere (the second layer of the atmosphere extending from about ten to 30 miles in altitude) has implications for ozone, stratospheric temperatures, and surface temperatures. While more water vapor in the stratosphere leads to ozone depletion there and a slight cooling of surface temperatures, this cooling is more than [...]

Sea-surface temperatures (SSTs) in the North Atlantic ocean fluctuate between warm and cool phases on periods of about 65-years, a phenomenon known as the Atlantic Multidecadal Oscillation (AMO). The AMO is currently in a warm phase. Warm phases result in enhanced precipitation over the tropical Atlantic, which causes changes in the upper atmosphere that lead [...]

In the Atlantic, the frequency of hurricane formation and the strength of the storms that form during a given year are controlled by things like Atlantic sea surface temperatures, temperature differences between the eastern and western tropical Pacific (i.e. the El Niño-Southern Oscillation) and even things like dust storm frequency in the Sahara Desert. On [...]

Phosphate, or PO4, is an important nutrient for marine algae, which form the base of the ocean food chain. Studies conducted off the coast of Japan indicate that the amount of zooplankton in this water corresponds to the amount of PO4 present. The amount of PO­4­ appears to be linked to the 18.6 year nodal [...]

Temperature and glacial extent records for the past few thousand years are generally more comprehensive for the Northern Hemisphere than for the southern. One of the major questions regarding the dynamics of the Holocene climate has been whether the relationship between the two hemispheres is in phase (they warm together and cool together) or antiphase [...]

Humans take about one-half million tons of shrimp out of the oceans each year. One North Atlantic species, the northern shrimp (Pandalus borealis), accounts for about 70 percent of this catch. These shrimp are largely bottom dwellers and have adapted their reproductive behavior to fit variations in temperature and salinity of the bottom water. During [...]

The movement of warm and cold water masses in the equatorial Pacific Ocean has long been known to affect circulation patterns in the upper atmosphere and thus weather conditions at remote locations throughout the world. A new and more complex relationship between weather conditions in the Tibetan Plateau, the equatorial Pacific, the North Pacific and [...]

A 1000 year record of sediment samples taken from Lower Mystic Lake (near Boston, MA) and four centuries of historical records chronicling weather events, land use changes and the relative abundance of different plant species, have been used to estimate the relative frequency of hurricanes over the past millennia. Historical records indicate that seven hurricane [...]

Records dating back to 1900 display a seven foot range in the variability of Lake Erie’s water levels, with the lowest values being reached in the early 1930′s and mid-1960′s, and high levels being seen 1950′s and 1980′s. Levels since 1999 have been below their long-term average. Periods of low water levels correspond to positive [...]

North America’s Atlantic salmon population, which return from the ocean to the rivers of their birth to spawn, have a freshwater breeding range that extends from the Connecticut River up to Canada’s Ungava Bay (at about 60 degrees North, roughly the same latitude as Oslo, Norway and Juneau, Alaska). The salmon overwinter in the southern [...]

During the spring months (March, April and May), the transport of aerosols (fine solid particles or liquid droplets suspended in a gas) from central Asia to the Pacific Northwest via the Pacific storm track is at its annual peak. There are three primary sources of these aerosols: industrial emissions; wildfires; and dust from the Gobi [...]

The Intermountain West (an area defined as higher than 4900 feet, encompassing Utah, Nevada, and parts of Oregon, Washington, Idaho, Montana, Wyoming, Colorado, Arizona, and New Mexico) receives most of its annual rainfall during the cold season. There is significant interannual variability in the amount of rainfall the region receives, which has been linked to [...]

The blast of frigid air that is invading the country this week will cause night time lows to drop below zero in much of the Northeast. While such frigid nights are not uncommon, they are less common than they were 50 years ago. The average temperatures of the 90th percentile for low temperatures (or the [...]

Average annual temperatures in Canada’s Northwest Territories (NWT) increased over the second half of the 20th century. Average winter minimum temperatures exhibited a particularly strong trend, with certain areas of the province showing 5.4 degree Fahrenheit increases. As this warming occurred, overall annual flow from NWT rivers has increased, particularly in the southern and central [...]