Climate data and models What they show us and how they can be used in planning BY Henri TONNANG

Definition of the “climate system” Source: NASA Definition of the “climate system” From the IPCC AR5 report: Climate System: “The climate system is the highly complex system consisting of five major components: the atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere, and the interactions between them. The climate system evolves in time under the influence of its own internal dynamics and because of external forcings such as volcanic eruptions, solar variations and anthropogenic forcings such as the changing composition of the atmosphere and land use change.”

Definition of the “climate system” Atmosphere: it is vital to maintaining life on Earth; the gaseous envelope surrounding the Earth. Hydrosphere: The component of the climate system comprising liquid surface and subterranean water, such as oceans, seas, rivers, lakes, underground water, etc. Biosphere (terrestrial and marine): The part of the Earth system comprising all ecosystems and living organisms… including derived dead organic matter, such as litter, soil organic matter and oceanic detritus. Cryosphere: All regions on and beneath the surface of the Earth and ocean where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers and ice sheets, and frozen ground (which includes permafrost). Lithosphere: The upper layer of the solid Earth, both continental and oceanic, which comprises all crustal rocks and the cold, mainly elastic part of the uppermost mantle

Definition of the “climate system” Source: Kiehl and threnberth (1997)

Weather vs. Climate Weather: Condition of the atmosphere at a particular time and place. Comprised of: Air temperature: Degree of hotness or coldness Air pressure: Force of the air above Humidity: Amount of water vapor in the air Clouds: Water droplets (liquid) or ice crystals (solid) above the surface Precipitation: Water that falls clouds and reaches ground Visibility: Farthest distance one can see. Wind: Horizontal movement of air

Surface Station Model

Wind direction NORTHERLY From the north WESTERLY EASTERLY 360° 270° 90° 180° WESTERLY From the west EASTERLY From the east SOUTHERLY From the south

Upper Air Measurements Weather balloons, or radiosondes, sample atmosphere up to 10 mb. They measure: Temperature Moisture Pressure They are tracked to get winds using global positioning satellites (GPS)

Upper Air Station Model (At specific pressure level)

Definition of Climate Climate: The statistical characteristics of weather elements over a given period of time. Some examples: Seasonal or yearly average rainfall Dominant patterns of sea surface temperatures (e.g. El Niño) Daily average temperature at a weather station Variability of snowfall

Climate variables Precipitation Weekly Monthly Seasonal Annually Temperature

Some Good Places on the Web for Climate Information National Weather Service www.nws.noaa.gov Climate Diagnostics Center, Boulder, CO www.cdc.noaa.gov Climate Prediction Center, NCEP, Camp Springs, MD www.cpc.noaa.gov Western Regional Climate Center, Reno, NV www.wrcc.dri.edu National Climate Data Center, Asheville, NC www.ncdc.noaa.gov .

Summary Defined the difference between weather and climate. Weather is the condition of the atmosphere at a particular time and place: temperature, pressure, humidity, clouds, precipitation, visibility and wind. Be familiar with how each of these is defined. Looked at surface and upper air station models (as well as weather symbols) and how to interpret them to diagnose the weather. Went through an example of a snowstorm in Colorado in late December. Climate is the statistical characteristics of weather elements over a given period of time. Several examples of climate data were presented for various time and space scales.