1. Describe what a greenhouse gas is and give examples of the common greenhouse gases. Why are greenhouse gases important to surface energy balance?

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect

Examples of common greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, Chlorofluorocarbons, and ozone.

Greenhouse gases strongly absorb the earth’s thermal infrared radiation, so they blanket the earth and reduce the cooling of the earth to space.
Without these so-called greenhouse gases, the surface of the earth would be about 30 degrees Celsius cooler, it is too cold for life to exist.

2. What is shortwave radiation? What is longwave radiation?

Shortwave radiation is basically radiant energy (light) in the visible, near infrared and near ultraviolet spectrum.

Longwave radiation is the energy leaving the Earth as infrared radiation at low energy to Space.

3. Trends in Atmospheric Carbon Dioxide - Mauna Loa http://www.esrl.noaa.gov/gmd/ccgg/trends/ Observed the plot and briefly describe the overall variation in CO2 from year 2009 to present and seasonality. What are the reasons for such a change in CO2, in your opinion, for the trend and seasonality respectively?

The level of CO2 has been increasing from 2009 to 2014. The trend is a upper slope. The red indicator has illustrate the seasonality.

Trend: In my opinion, the urban industry has a big impact on the exhaust of CO2. Coal and fossil fuel burn release huge amount of CO2. The modern activities have speed up the producing of CO2. Forest fire also has a big impact on the CO2 level increase. The massive tree burn can also release CO2 in a big amount. That is my opinion for CO2 increase.

Seasonality: During the fall and winter, vegetation