Temperature Flashcards
The formula to calculate fahrenheit from centigrade:
C x 1.8 + 32
The re-radiated heat from the earth is in the form of -
The heat received from the sun is in the form of -
long wave radiation/insulation or infra-red.
Short wave radiation/insolation or ultra-violet
It is important to note that the atmosphere is not heated -
directly from the sun’s radiation, but that the majority of its heating occurs from re-radiated long wave energy.
Cloud, water vapour and carbon dioxide absorb -
long wave energy(infra-red) thus trapping the energy. This temperature rise is called the greenhouse effect
Energy in by day is from -
Solar radiation(short wave insolation)
Energy out by day and night is from -
terrestrial radiation(long wave insulation)
Is air a very poor or good conductor of heat?
Very poor
Explain convection:
In meteorology convection is heat transfer during vertical motion induced by local disturbances. When the lower portions of a fluid like air(air is a fluid) is heated it expands and the density reduces and then rises taking it’s heat with it. Cooler air then replaces the risen air which then heats again and the cycle repeats.
Explain advection:
This is the process of heat transfer by horizontal motion(wind). As warm air rises in vertical motion, the cooler surrounding air moves in to replace the lifted air.
Between water and land, which require more energy to be heated?
And which will lose its energy faster(at night)?
Water.
Land, water retains its heat longer.
The daily maximum temperature will occur at?
14:00 local time
Short definition of an inversion -
triggering conditions -
Under what conditions is it destroyed -
Under what conditions will it persist -
An inversion is a reversed lapse rate, which means an increase in temperature with height.
The formation of a ground inversion may occur on clear nights when terrestrial radiation is at a maximum. An inversion may also form during the day when warm air mass passes over a very cold sea or land surface.
An inversion is destroyed with sunshine
Will persist during the day under conditions of cloud cover or by the presence of fog.
When a layer occurs in which the temperature is constant with an increase in height, it is called -
an isothermal layer
The ELR is steep the decrease in temperature with altitude is -
The ELR is shallow the decrease in temperature with altitude is -
If the ELR is 2 degrees of temperature decrease per 1 000ft, the ELR is -
During an inversion the ELR is -
With an isothermal layer the ELR is -
great
small or little
Positive
Negative
Zero
Diurnal Variation:
The sun is at its highest elevation at ____, but for two to three hours after this time, the earth is receiving more solar radiation than it is giving up as terrestrial radiation. A balance between incoming and outgoing radiation is reached on average at ____ local time when _______ temperatures can be expected.
From ____ onwards, the temperature falls continuously until a little after sunrise. The lowest temperature occurs at about sunrise plus __ minutes when once again we get a balance between incoming and outgoing radiation.
Diurnal Variation (DV) is greatest with ____ ___ and little ___. DV varies with a number of factors, but in temperate latitudes is about +/- _ degrees about the mean.
The sun is at its highest elevation at 12:00, but for two to three hours after this time, the earth is receiving more solar radiation than it is giving up as terrestrial radiation. A balance between incoming and outgoing radiation is reached on average at 1500 local time when maximum temperatures can be expected.
From 15:00 onwards, the temperature falls continuously until a little after sunrise. The lowest temperature occurs at about sunrise plus 30 minutes when once again we get a balance between incoming and outgoing radiation.
Diurnal Variation (DV) is greatest with clear skies and little wind. DV varies with a number of factors, but in temperate latitudes is about +/- 6 degrees about the mean.
Diurnal Variation:
What is the effect of cloud cover by day on the diurnal variation?
And why?
What is the effect of wind by day on the diurnal variation?
And why?
The maximum temperature is reduced
Cloud reflect the short wave radiation
The maximum temperature is reduced
By day wind will cause turbulent mixing of the warm air at the surface with cold air above
Diurnal Variation:
What is the effect of cloud cover by night on the diurnal variation?
And why?
What is the effect wind by night on the diurnal variation?
Temperature minimum is increased
terrestrial radiation is absorbed and radiated back to the earth’s surface from the clouds.
Temperature minimum is increased
By night there will normally be an inversion above the surface and wind will cause cold air to be turbulently mixed with warm air above
Explain why the DALR and SALR behave the way they do, and their values -
Imagine a bicycle pump - As the air is forced to compress, it will heat up. Conversely, if it is forced to expand(imagine a compress bottle of air, and the valve open) it will cool. Same applies with the atmosphere.
Dry air which is force to rise will cool at the DALR of 3 degrees/1 000ft.
Saturated air which is forced to rise will cool at the SALR of 1.5 degrees/1 000ft.
The reason why the SALR is lower than the DALR, is because condensing air releases latent heat.
Stability can be defined as being -
Resistance to change
Conditional instability:
Is the air is saturated, it will -
If the air is dry -
Neutral stability:
Rise
Resisting rising(DALR > ELR > SALR)
ELR = DALR = SALR
The SALR and DALR in degrees per metre is -
SALR - 0.6/100m
DALR - 1/100m
The ELR is -
