Rotorua Weather Data - Geyserland Observatory
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Precipitable Water Vapor (cm)

Water vapor is the most abundant of the greenhouse gases in the atmosphere and the most important in establishing the Earth's climate. Greenhouse gases allow much of the Sun's shortwave radiation to pass through them but absorb or trap the longwave, infrared radiation emitted by the Earth's surface. Without water vapor and other greenhouse gases in the air, surface air temperatures would be well below freezing.
There is always much less water vapor in winter than summer.

The graph shows total water vapor (precipitable water) at Geyserland Observatory at solar noon, when the Sun is not obscured by clouds. Also added into the graph are temperature at the time of reading.

Graph's starting at the beginning of August 2005 and are going to be updated at the beginning of every following month.




Haze

Haze, caused primarely by Mie scattering, is from tiny particles or droplets suspended in the atmosphere. The particles and droplets that cause haze are called aerosoles. They include dust, smoke, soot, salt, ice, pollen, spores and tiny droplets of liquid water that condenses on very small aerosoles increases haze and leads to the development of clouds.
On a hazy summer day, people with light skin can receive a sunburn in the shade. This is because most of the Sun's ultra violet radiation is received from the hazy sky instead of the direct Sun.
Not all haze is produced by people. Smoke from large grass and forest fires can cover entire countries. When the volcano Mount Pinatubo erupted in 1991, it propelled some 20 million tons of sulfur dioxide into the stratosphere. The gas eventually became tiny droplets of sulfuric acid that remained high in the sky for several years. This volcanic haze blocked more than 10% of sunlight over much of the Earth and caused the Earth to cool by a degree or two Celsius for more than a year.
The graph below (data taken at solar noon) shows the percentage of sunlight transmission true the aerosole optical thickness (AOT). (95-98% is pretty clean air; 82% thats a bit hazy)Also added into the graph are temperature at the time of reading.




Photosynthetic Active Radiation (PAR)

The amazing ability of plants to change carbon dioxide and water into carbohydrates is called photosynthesis. Chlorophyll is the very special molecules responsible for photosynthesis. Sunlight powers photosynthesis, with blue and red wavelengths of sunlight being the most effective. These wavelengths are known as Photosynthetically Active Radiation (PAR).
Each measurement was made at solar noon on a clear day. The graph shows how PAR changes with the seasons. PAR is much higher in summer than in winter. The graph also shows changes in PAR caused by haze, smoke and clouds. While all of these reduce PAR, clouds near the sun can reflect sunlight toward the ground and cause a temporary increase in PAR.

The unit of measurement (left side of graph) is micromoles per second per square meter ( µmol s -1 m -2 ).



The instrument used for collecting the data is a Sun photometer and/or solar radiometer, working with a GREEN sensor (peak response at about 525 nanometers (nm)); RED sensor (peak response at about 620 (nm); IR1 sensor which has a peak response in the near-infrared at about 816(nm) and a IR2 sensor, this sensor has a peak response in the near-infrared at about 940 (nm).