weather and environment ch 4.5.13.6.7.8
at what rate does unsaturated air cool when it rises through the atmosphere?
10 degrees C for every 1000m in altitude
how much more acidic is a substance with a ph of 4 than a substance with a ph of 6?
100 times more acidic
suppose that the air temperature is 20C and the relatively humidity is 50 percent at 6pm, and that during the evening, the air temperature drops, but its water vapor content does not change. If the air temperature drop 1C every 2 hours will fog occur by sunrise 6am the next morning?
14C greater than dew point temperature. No fog will occur by sunrise
if unstaurated air at 20 degrees C were to rise, what would its temperature be at height of 500 meters? if the dew point temperature at the lifting condensation level were 11 degrees C, at what elevation would clouds begin to form?
15 degrees C at 500m. 600m elevation clouds begin to form.
why does the adiabatic rate of cooling change when condensation begins?
As air moves up through atmosphere, decrease in temperature, unsaturated air cools at a constant rate until the air reaches dew point and condensation begins. When air reaches saturation state the latent heat that's absorbed during evaporation is released as sensible heat. Even the cooling rate continues adiabatically as the heal released slows the rate of cooling.
why does air expand as it moves upward through the atmosphere?
As air moves upward through the atmosphere the pressure gradually decreases due to gas and internal energy decreases, in which the air expands and cools adiabatically.
describe the temperature conditions in clouds that are required to form precipitation by the bergeron process
Cold clouds at temps below 0C have water droplets and ice crystal and both are coexisting. Pure water droplets suspend in air will not freeze at zero degrees Celsius as in the general case. Pure water droplets attains the state of ice crystals at a temperature of -40C and water in the liquid state below 0C known as supercooled water. THe supercooled water droplets become ice crystals when it hits any solid particles. These particles are known as freezing nuclei and most active in the thermal range between -15C and -40C. The main assumption of Bergeron Process water droplets in the clouds will not freeze until a water droplet touches a thermal level well below 0C.
distinguish between clouds and fog
Difference is the place and process of formation. Clouds form at higher altitudes above earth's atmosphere whereas fog is formed at the lower surface of groud. Clouds are formed when air rises and cools adiabatically. Fog is formed on cooling or when air becomes saturated on addition of water vapor
describe how an el nino event might affect the climate in North America during the winter. Describe the same for a la nina event.
El nino brings warmer conditions more severe than the normal ones; last for nine months to two years. La nina is opposite to el nino and brings colder conditions and more severe than normal ones
explain the difference between environmental lapse rate and adiabatic cooling
The air stability is calculated by measuring the temperature of the atmosphere at different heights or different locations is the environmental lapse rate. Environmental lapse rate is the temperature of the atmosphere that is found from radio-sone and aircraft observations. The adiabatic temperature change is the change in temperature that is responsible for expansion or compression as an air parcel tends to rise or descend.
for surface low pressure to exist for an extended period, what condition must exist aloft?
The compensation takes place at layers that are aloft for existence of surface low for a long time. surface convergent to be maintained if divergent aloft takes place at equal rate of below flow.
how does a major la nina event influence the hurricane season in the north atlantic?
The impact of the la nina event on the Atlantic ocean is more frequent hurricane activity. across the tropical atlantic, the la nina produces easterly wind departures at upper levels of the atmosphere and westerly wind departures at lower levels. these wind patterns lower the vertical wind shear and tends to be more atlantic hurricanes.
how is stability of air determined?
When the temperature difference between the air near the surface and the air at the top is very small.
describe the process of cloud formation
a cloud is a collection of water droplets in the atmosphere. In the atmosphere, water vapor condenses to form clouds. When a parcel of air rises above the atmosphere, the air expands and cools adiabtically. When this air reaches its dew point it starts condensation resulting in the formation of clouds.
it's a warm summer day, and you are shopping in downtown chicago, just a few blocks from lake michigan. All morning the winds have been calm, suggesting that no major weather systems are nearby. By afternoon, should you expect a cool breeze from lake michigan or a warm breeze originating from the rural areas outside the city?
a cool breeze would iniate flowing by the midafternoon from the lake resultant pressure due to the temperature differences between the lake and the land. The land is warm and the water is cool; the air above land moves towards the lake and the cooler air of lake moves towards the land. A warm breeze will not originate from the rural areas outside the city because the impact of the cool breeze from the nearby lake michigan would influence the air.
what is an isobar
a countour line of pressure of atmosphere can have different levels of atmosphere and the line connecting equal value of pressure. used to map the atmosphere or air pressure in ways that makes it easier to understand
what are some environmental effects of acid precipitation
acid rain accelerates the chemical weathering of structures and the corrosion of metals. This can result in the degradation of the structures made from metals and stones. The plant population in the forests and productivity in the agriculture is also hampered because of the increase in acid content of soil
what name is given to the processes whereby the temperature of air changes without the addition or subtraction of energy?
adiabatic temperature changes
what do the lowercase letter sk and w indicate about an air mass? list the general weather conditions associated with k and w air masses
an air mass is colder than the surface over it is moving is k. an air mass is warmer then the surface over it is moving is w. k is getting heat from the surface and becomes less stable. thunder/showers. W is getting cold temperatures and becomes more stable. light/moderate precipitation
explain why pressure decreases with an increase in altitude
at higher elevations, there are fewer molecules as compared to lower level of the surface. Pressure is lower that higher levels and vise versa.
compare the temperature and moisture characteristics of the following air masses: cA, cP, mP, mT, and cT
cA: dry/low moisture content, extremely cold cP: dry/low moisture content, cold cT: dry/low moisture content, warm mP: high moisture content, cold mT: high moisture content, warm
explain the formation of geostrophic wind and describe how geostrophic winds blow relative to isobars
caused by the balancing of coriolis effect and pressure gradient force. Frictional forces not responsible for these winds
write a generalization relating to the spacing of isobars to wind speed
closely spaced isobar corresponds to higher wind. Widely spaced isobars correspond to light wind.
describe the atmospheric pressure associated with a cyclone compared to an anticyclone.
cyclones occur in a place where the atmospheric air is having low value compared to the surrounding region. Anticyclones occur in a place where the pressure atmosphere is greater than that of the surrounding region.
if you live in the northern hemisphere and are directly west of the center of a midlatitude cyclone, what is the probably wind direction?
cyclones rotate counter-clockwise in the northern hemisphere. If we are at west of the center, the winds would be coming at us from the north. So, the direction of the wind would be southerly
on what basis are air masses classified?
depending on region of the source. areas where an air mass attains the properties of temperature and moisture is called source region
what weather condition would lead you to believe that air is unstable?
formation of towering clouds and heavy precipitation
how does hail form? what factors govern the ultimate size of hailstones?
hail is the precipitation in the form of lumps of ice. Generally it forms only in the cumulonimbus clouds. When small pellets of ice passes through the supercooled liquid resulting in the additional layer of ice to form large hailstones. Size determined by hitting updraft or downdraft not being able to support it.
what are the two criteria by which clouds are classified?
height and shape/form
how does stable air differ from unstable air?
in a stable air, the parcel of air will be cooler than its environment, resists the upward motion and spreads horizontally in relatively thin layers. If the parcel of air forces to rise, it will sink back to its original position. Unstable air is warm and moist and easily rises up until it reach the temperature equal to the surrounding air temperature.
Briefly summarize the collision-coalescence process
involves multiple collisions of tiny cloud droplets that stick together to form raindrops large enough to reach the ground before evaporating.
identify the two factors that influence the magnitude of the coriolis force
latitude and wind speed. Latitude is at max at poles and decrease as we move towards equator. higher wind speed is accompanied by higher coriolis force
which two air masses have the greatest influence on weather east of the rocky mountains? explain your choice
mT air masses are warmer and humid and unstable. However, north atlantic mT air masses are usually unstable because the source region is located on the weak western edge of the anticyclone, where pronounced subsidence is absent. During winters, cP and cA air dominates the rockies and mT air only occasionally affects the weather.
where in the U.S. is precipitation most acidic?
northeastern U.S.
why is the flow aloft in the midlatitudes predominately westerly?
over the equator the temperatures are high, air pressure decreases more gradually than over the cold polar regions. Consequently, the same altitude above Earth's surface, higher pressure exists over the tropics and lower pressure is the norm above the poles. Thus, the pressure gradient aloft is directed from the equator toward the poles. Once the air from the tropics began to advance towards the pole in response to this pressure gradient force, the coriolis force causes a change in the direction of air flow. Eventually, a balance is reached between the pole ward directed pressure gradient force and the equator directed coriolis force to generate a wind with a strong west to east wind flow called westerly.
what weather condition would lead you to believe that air is stable?
radiation cooling of earth's surface after sunset, cooling of air due to cold surface, cooling within the air column
what determines the terminal velocity of objects?
speed of the falling object. gravitational force balanced with a resistive force falling at a constant velocity known as terminal velocity.
describe how a major el nino event tends to affect the weather in peru and chile as compared to indonesia and australia
strong equatorial counter currents accumulate warm weather and flows towards the eastward of pacific. these winds movements are from south america to australia and indonesia. some inland areas of peru and chile that are normally arid receive above-average rainfall, which can cause major flooding. El nino has major impact on the climate of north america and affects the tropical pacific areas.
why does florida have abundant midafternoon thunderstorms?
the air flow is from ocean to land along both coasts of florida. When this air converges, the air lifts up causing the intense solar heating of the land which results in the highest frequency of midafternoon thunderstorms.
what two criteria must be met for an area to be an air- mass source region?
the area under consideration must be an extensive and physically uniform area. A region having highly irregular topography or one that has a surface consisting of both water and land is not satisfactory. The area must be characterized by a negligible atmospheric circulation so that air will stay over the region and will be able to come to equilibrium with the surface. In other words , the regions must be dominated by stationary or slow-moving anticyclones, with their extensive areas of calm or light winds
describe sleet and freezing rain. Why does freezing rain result on some occasion and sleet on others?
the droplet of rain freezes and falls on ground when rain passes through a layer of cold air. The crystals of ice droplets are called sleet. Generally sleet is formed in winter, when warm air is passed over a layer of sub-freezing air. Freezing rain or glaze is formed when super cooled water freezes on contact with the objects on the ground
the most intense sea breezes develop along tropical coasts adjacent to cool ocean currents. Explain
the intense solar heating is continuous throughout the yaer. This leads to more temperature difference or pressure difference between the sea and adjacent land areas. Water winds are originated over water, blow towards the land area and create more intense sea breezes
at what time of year should we expect the fastest polar jet streams? explain
the large pressure gradients aloft are produced due to the temperature differences on the surface of the earth during winter and results in faster upper air winds. in winter time due to these large temperature contrasts lead to fastest westerly flow at that time of year. These large temperature contrasts occur along linear zones called fronts. This fastest westerly flow along frontal zones called polar jet stream.
what is supercooled water?
waterdroplets having temperature below 0C. Cause freezing rain.
what is wind and what generates it?
wind is the horizontal displacement of air particles and this occurs when atmospheric pressure difference exists. Wind flows mostly around high and low pressure air since wind is deflected to the right in N hemisphere and left in S hemisphere
