Key Words: vertical mean temperature, radiosonde, aerosol, global warming, cooling
Abstract
Recently climatologists have indicated that the global warming is currently happening as a result of human activities. Such evidences were shown by the increasing trend of surface temperature that taking place at a number of big cities and industrial areas all over the world. This just brings impact on microclimate but it doesn't have much influenced for the atmospheric mean temperature.
In fact, the analysis result of the atmospheric mean temperature based on radiosonde data observed in several big cities in Indonesia show the cooling between -2.730 and -5.510 from its normal. This indicates that nuclei condensation (aerosol) particles on the atmosphere over Indonesia were quite abundant. It can be related with the fact that Indonesia is an archipelago consists of thousand of islands - 70 % of Indonesian region is ocean.
On the other hand we can assume that the global warming that is usually connected with surface temperature cause the increasing of evaporation from ocean. And these aerosols will be trapped at mixing layer and cannot go higher. So that the propagation of sun radiation will prevent from going through and this cause the cooling temperature of atmosphere in this layer. The problem is how far from the surface that the global warming can affect the atmospheric layer.
1. Introduction
The symptoms of heat increase of the earth surface have become the growing concerns for scientists. Many theses have been proposed to find the causes of increasing global temperature. The increases have been taking place since the industrial revolution up to now. The main factor considering have role in global warming process is green house gases in the atmosphere.
It is believed that green house gases have an effect to trap heats. When the concentrations of the atmospheric green house gases increases, it will occur heat energy oscillation between earth surface and the atmosphere with green house gases content. The result is the air becomes hot and this condition is identified by the increase of mean temperature. The United State-Global Change Research Information Office (US-GCRIO) predicted that the earth temperature has increased 0.3 - 0.6o C during the last period of 19th century.
The increase of earth surface heat causes smelting of glacier resulting sea level rises. However, besides some regions have earth surface heat increase, the mean temperature in the other regions decreased (cooling process), This is probably because the effects of energy balance process occurring on the globe. If there is a changing action within a certain physical condition such as temperature increase in several areas, re-action will take place in to achieve equilibrium energy in other locations. It is believed that the total energy on the globe is always fixed. There is no energy lost but it can alter to be other form.
This study will explain the fluctuation or variation of vertical mean temperature in Indonesia regions and look the possibilities of global climate change impacts to the boundary layer atmospheric conditions. This study used 1994 to 1998 upper air data from 11 radiosonde stations in Indonesia regions.
2. Theoretical Overview And Data
2.1. Theoretical Overview
Atmospheric heating is basically taken place due to the interaction between solar radiation and any gases in the atmosphere. It is known that the atmosphere consists of various gases: permanent and impermanent gases; solid and liquid particles such as aerosol, ice crystal and water rainfall.
The permanent gases: nitrogen; oxygen and argon are almost 99.9% of total gases in the atmosphere. Such gases have fixed volume over 60 kilometers height. It is important to be noticed that CO2 is also considered as a permanent gas with various level of concentrations due to the result of fossil fuels burning. CO2 sinks into the ocean or is absorbed by plants by way of photosynthesis.
Atmospheric water vapor content varies every time depending on the atmospheric condition. The variation of water contents in the atmosphere is important because it relates to absorption and emission process of solar radiation. Furthermore, ozone concentration also varies from time to time. The concentration variation can be clearly seen on vertical direction with 15-30 Km height from the earth surface.
Ozone is generally formed in stratosphere layer. In mesosphere area, air temperature also decrease toward height from 50-85 kilometer. The layer above mesosphere area is called thermosphere layer. Air temperature in this layer is about 500o K to 2000o K. The outside of thermosphere layer is exosphere layer.
In meteorology air temperature and humidity in every atmospheric layer up to 20 km height can be determined by releasing radiosonde balloon. The vertically atmospheric mean temperature can be calculated by using the following formula (Bevis, et.al):
Pv and T are water vapor partial pressures (mb) and temperature. pv value is described as follows:
where T = temperature at certain height in absolute degree (° K); Ts = vapor point temperature (273.6o K) and ew= saturation water pressure at 273.6° K. (1 atmospheric standard = 1013.246 mb).
