Davis Instruments Vantage Pro2 User Manual

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from the sun and the reflected component from the rest of the sky. The 
solar radiation reading gives a measure of the amount of solar radiation hit-
ting the solar radiation sensor at any given time, expressed in Watts/sq. 

meter (W/m

2

). Solar radiation requires the solar radiation sensor.

Energy from the sun reaches the earth as visible, infrared, and ultraviolet 
(UV) rays. Exposure to UV rays can cause numerous health problems, 
such as sunburn, skin cancer, skin aging, cataracts, and can suppress the 
immune system. The Vantage Pro2 helps analyze the changing levels of 
UV radiation and can advise of situations where exposure is particularly 
unacceptable. UV radiation requires the UV radiation sensor. The Vantage 
Pro2 displays UV readings in two scales: MEDs and UV Index. 

Note: 

Your station’s UV readings do not take into account UV reflected off snow, sand, or 
water, which can significantly increase your exposure. Nor do your UV readings  take 
into account the dangers of prolonged UV exposure. The readings do not suggest 
that any amount of exposure is safe or healthful. Do not use the Vantage Pro2 to 
determine the amount of UV radiation to which you expose yourself. Scientific evi-
dence suggests that UV exposure should be avoided and that even low UV doses 
can be harmful.

MED (Minimum Erythemal Dose) is defined as the amount of sunlight 
exposure necessary to induce a barely perceptible redness of the skin 
within 24 hours after sun exposure. In other words, exposure to 1 MED 
will result in a reddening of the skin. Because different skin types burn at 
different rates, 1 MED for persons with very dark skin is different from 1 
MED for persons with very light skin.

Both the U.S. Environmental Protection Agency (EPA) and Environment Canada 
have developed skin type categories correlating characteristics of skin with rates of 
sunburn. 

 

1 - Never tans,

 always burns

Pale or milky white; ala-

baster

Develops red sunburn; painful swelling, skin 

peels

2 - Sometimes tans, 

usually burns

Very light brown; some-

times freckles

Usually burns, pinkish or red coloring appears;

can gradually develop light brown tan

3 - Usually tans,

sometimes burns

Light tan; brown, or olive;

distinctly pigmented

Rarely burns; shows moderately rapid tanning 

response

4 - Always tans;

rarely burns

Brown, dark brown, or 

black

Rarely burns; shows very rapid tanning re-

sponse