Beginning with
the daily and annual cycles and using the power of ten to view longer
time scales, Climate Science provides insight into how scientists use
data to study climate variability. See an overview
of climate processes for general background on Earth's climate system.
This
graph is a reconstruction of lake salinity for Moon Lake, ND. The data
(from Laird, et. al., 1996) indicates
that the region was generally drier in the early part of the record than
in more recent centuries, with an abrupt climate
change around 1200 A.D. when the climate shifted from a pattern of
regular droughts lasting decades to a wetter climate.
Because records
from instruments such as rain gauges and thermometers are limited in their
scope, we examine the past climate record using "paleoclimate proxies"
such as tree rings and ice cores to reconstruct past climate events. Patterns
can be found in many of these natural recorders such as the annual cycle
which can leave annual bands in trees, ice caps and some types of coral,
and longer term orbital cycles such as precession which are thought to
trigger major Ice Age events.
In recent years a large array of climate related dated has been compiled
and analyzed. Some questions about climate dynamics have been answered,
but the research has revealed the complexity and "nonlinear"
nature of many of the systems and processes, raising new questions. Moreover,
there remains significant debate and in some cases disagreement in the
scientific research community about the nature and implications of these
dynamics. Is the El Niño-Southern Oscillation really an oscillation?
What role does water vapor- an important greenhouse
gas- play in increasing or decreasing global warming? Has climate
triggered disease outbreaks? How do various forces that generate climate
change interact with each other?
Weather's variability occurs quickly, in the period of hours
and days, and while extremes between high and low temperatures
or abrupt storms can occur on such small time scales, they are
influenced by longer-term climatic forces.
Scientists are finding that even with as much information as they
have gathered about current and past weather and climates, it
is difficult to predict weather beyond an 11-14 day time horizon.
Forecasting longer-term climate also proves challenging, although
some scientists have a strong track record of predicting tropical
storm patterns or the climatic consequences of El Niño
type events some months in advance. See Future
Forecasts for more.
FORCING
FACTORS
Weather and climate are influenced
by a variety of factors such as:
-astronomical factors such as the tilt of the Earth's axis
-the climate character of a region
-the time of year/season
-the time of day
-volcanic activity
-chemical composition of the atmosphere, including the influence
of human impacts such as heat from cities, agriculture practices,
and the burning of fossil fuels.
Characterizing
Climate
Oceans cover over 70% of the planets surface and their ability to retain
and release heat make them one of the major drivers of weather and climate.
ENSO (El Niño Southern Oscillation),
PDO (Pacific Decadal Oscillation), NAO (North
Atlantic Oscillation) and the Thermohaline Circulation
(THC) are among the ocean dynamics that may influence climate patterns.
The above image is an animation of recent anomalies or irregularities in
sea surface temperature (or SST) in the Pacific ocean.
Images (top to bottom) from CLIVAS, NOAA Photo Library, NGDC and CDC/NOAA.
http://www.ncdc.noaa.gov/paleo/ctl/clisci.html
Downloaded Tuesday, 16-Sep-2008 09:07:03 EDT
Last Updated Friday, 07-Oct-2005 12:25:59 EDT by
paleo@noaa.gov
Please see the
Paleoclimatology Contact Page or the
NCDC Contact Page if you have questions or comments.
This
graph is a reconstruction of lake salinity for Moon Lake, ND. The data
(from 
