Hydrology and Atmospheric Processes: Key Concepts

Fundamental Questions in Hydrology and Meteorology

What is the largest flux in the global water cycle?

Evapotranspiration

What is NOT considered precipitation?

Fog

Air masses lift as they converge on a low pressure zone. This is what type of lifting?

Convergence

An air mass lifts as a colder, denser air mass moves towards it. This is what type of lifting?

Frontal

What surface water body would have the greatest rate of evaporation?

Small, shallow, freshwater

Which factor does NOT significantly influence transpiration?

Soil color

What is the most accurate way to measure evaporation from an open water body?

A floating evaporation pan

Sublimation from Snow: Key Characteristics

Sublimation from snow is typically low because:

• The saturated vapor pressure (e sub s) is very low at cold temperatures.
• Most energy is used to melt the snow (latent heat of fusion).

What meteorological factor influences evaporation the most?

Solar radiation

If the saturated vapor pressure is 2.0 kPa and the air vapor pressure over a water body is 1.5 kPa, what process occurs?

Evaporation (due to the positive vapor pressure gradient)

Where is water velocity likely to be fastest in a straight stream channel?

In the center of the stream, near the surface.

Which statement about groundwater is INCORRECT?

1. It typically dissolves minerals it comes in contact with, changing its chemistry.
2. It can help reduce drought as it is a relatively constant supply of water to lakes, rivers, etc.
3. It is a larger global reservoir of water than glaciers and ice caps. (This statement is false; glaciers and ice caps hold more water.)
4. It is used by many people worldwide as drinking water, and for agriculture and industry.

Three Steps of Cloud Formation

1. Moisture Input: Evaporation occurs from a water body or moisture is released to the atmosphere via biological transpiration.
2. Adiabatic Cooling: The warm, moist air rises through the atmosphere and begins to cool adiabatically (without the loss or gain of heat to the surroundings).
3. Approaching Saturation: The warm, moist air is not at the saturation point in the lower regions of the atmosphere, but as it rises and cools, it approaches saturation.

Rain Gauges: Recording vs. Non-Recording

Non-Recording Rain Gauge

• Generally used to determine total rainfall over a certain time period (which may range between 24 hours and several months).
• Does not provide information about rainfall intensity.

Recording Rain Gauge

• Provides information about rainfall intensity.
• Uses tipping buckets or weight mechanisms to determine how much rain falls in a set period of time, and this information is automatically recorded.