Heat, Temperature and Atmospheric Circulation

Temperature and Heat Temperature –Proportional to average kinetic energy of atoms/molecules of substance Heat –Energy in transit, if two objects are at different temperatures, energy is transferred

Temperature Scales Celsius ( o C)-1742 –100-degree –Boiling (100 o ) & freezing (0 o ) point of pure water at sea level Fahrenheit ( o F) –Also based on phase changes on water –Boiling (212 o F); Freezing (32 o F) Kelvin (K) –0 K, Absolute zero o C –Freezing point of water K; boiling point K

Conversion Formulas o F = 9/5 o C + 32 o o C = 5/9 ( o F – 32 o ) K = 5/9 ( o F ) K = o C

Measuring Air Temperature Thermoscope- Galileo 1592 Thermometer –Alcohol –Mercury Thermograph –Bimetallic sensing element –Brass-iron –Pointer calibrated to read in o C o F –Continuous trace of temperature with time

Conduction & Convection Convection is the transfer of heat by the actual movement of the warmed matter (fluids-liquids and gases) Conduction is the transfer of energy through matter from particle to particle (collision of particles) Radiation is BOTH a form of energy and a means of energy transfer (it can travel through a vacuum)

Phase Changes of Water Heat is ABSORBED from the environment during: Melting, Evaporation, Sublimation Heat is RELEASED to the environment during: condensation and precipitation

Bowen Ratio A Bowen ratio is the ratio of energy fluxes from one medium to another by sensible and latent heating respectively. It is calculated by the equation where Qh is sensible heating and Qe is latent heating. Global Bowen ratio is 0.3

Comparison of incoming solar radiation outgoing and outgoing long- wave radiation with latitude. Energy transfer is required to maintain a balance

Thermohaline Circulation The thermohaline circulation is the global density-driven circulation of the oceans Wind-driven surface currents (such as the Gulf Stream) head polewards from the equatorial Atlantic, cooling all the while and eventually sinking at high latitudes This dense water then flows into the Ocean Basins

Satellite image of warm and cold eddies spinning of the Gulf Stream

Cold & Warm Air Advection Cold/Warm air advection is the process in which the wind blows from a region of cold/warm air to a region of warmer/cooler air Winds are blowing from a region of cooler/warm air to a region of warmer/colder air, which results in a cooling/warming of the warmer/colder region. As the colder/warm advection persists, temperatures in the warmer/colder region will begin to decrease/increase as the colder/warmer air moves into the region of warmer/colder air.

Heating degree day Heating degree day (HDD) and cooling degree day (CDD) are quantitative indices designed to reflect the demand for energy needed to heat or cool a home or business. These indices are derived from daily temperature observations, and the heating (or cooling) requirements for a given structure at a specific location are considered to be directly proportional to the number of heating degree days at that location.

A heating degree day is defined as: 65°F - mean daily temp Mean Annual Heating degree days over the U.S. in thousands