Saturday, November 26, 2005

Whether to Wither Weather

Water an elixir of life... Really? Hastily said? I guess so..

Floods everywhere in South India. Reading this I could recall the last summer when the peninsula was sore without water. Farmlands literally sun baked without water but now, swept clean by floods. Why this extreme variation in climatic conditions? Shall not this excess water be tapped in the right way and made use of during the needy times? This remains as the unanswered question of virtually everyone in the State. Unbearable hot summers followed by flooding monsoons, will these continue as the eternal plight of tropical countries? Can weather be tamed?
Fortunately the answer seems to be positive.

Now lets learn how hurricanes (deadliest of climatic demons) are formed and how could those be tamed.

Hurricanes (called as Cyclones in the Indian Ocean, Typhoons in the Pacific Ocean) are spiraling winds at the speed of 75 miles per hour (65 knots) formed in the tropics. When these winds strike heavily populated areas, they can kill thousands and cause billions of dollars of property damage. Nothing stands in their way.

Anatomy of a Hurricane
Formation of these tempestuous storms is depicted in the picture. 1.High temperatures at the lower latitudes of tropics cause high evaporation rates. 2.The moist, warm air raises upward and as it reaches cooler altitudes, the moisture condenses releasing the latent heat of evaporation (3) thus causing them rise to further heights.

4.The fast rising air creates a region of low pressure
below. Air form the surrounding flow into this region of low pressure. This causes the air above to rise further (5). This movement and release of heat cause further inflow of air at the bottom. 6.The storm gets a circular rotating action due to the rotation of earth.

7. This process continues rapidly increasing the quantity of inflow creating a familiar central eye and few others layers of winds each at different temperatures and levels of saturation.
8.The spiraling air forms a wall around the center resembling a cylinder. 9.The rising air looses much of its moisture and temperature as it reaches the lower layers of stratosphere and is centrifuged away (shown in blue arrows). Some part of it falls into the eye.

The logic behind controlling hurricanes is that atmosphere is greatly sensitive to tiny influences. These slight, purposely applied inputs to a hurricane might generate powerful effects that influence the storms either by steering them off the track or by reducing their wind speeds.

The Simulation
Scientists at Atmospheric & Environmental Research (AER) with the funding form NASA, model hurricanes and simulate them with 3D soft wares. They use ‘time’ as an extra dimension making it a 4D model.
To create the model, six hours data (of a recorded storm) providing details about the humidity, wind speed and direction, temperature at different altitudes are fed. The model is simulated and a realistic hurricane is seen as an animation. Every inch of it is studied at every second interval.
Now this model can be used to visualize how the storm would look if took a different path. The egregious harm due to the storm would be minimal if it had skipped human settlements. So as the model is being simulated, scientists try to change or detour the path of the hurricane, diverting it away form densely populated regions by giving specific commands to the computer. The computations were made to provide the smallest change needed that can powerfully alter the course of the storm.
Several trials were made and the final observations revealed that the most significant modifications were located at the starting temperatures of winds. Meaning that altering the initial temperatures of the hurricane (the evaporation state) would result in massive changes in the path of the storm. A slight change of a mere 1/10 of a degree Celsius(during the initial state) caused a terrific shift of about 500 miles off the original track, and an alteration of 3 to 20 (mph) in velocity and a 2 degree temperature change

Further analysis revealed the necessity for an alteration of about a few degrees in temperature to arrive at quick results. With the present technology, the possibility of raising the temperature of something as huge as a hurricane seems remotely possible.

In the future, an array of earth orbiting satellites can convert solar energy into microwaves and beam them at the target location to heat them up. This would cause a shift into the desired direction. In addition biodegradable oil could be spread over the sea surface. This would reduce the evaporation causing lesser air to ascend thus reducing the intensity of the storm. Artificial condensation aids by seeding the clouds with silver iodide would cause immediate precipitation lessening the severity of the storm.

The sporadic nature of weather makes it all the more difficult to model. Thus no matter to what extent we strive to mimic the chaos an exemplary model cannot be achieved. Due to the lack of sufficient records all hydrologic cycles are believed to close annually.
This ability to alter the course of a tempest could be used to devastate enemy countries by economically and electronically sound nations. Hence a UN policy has banned the usage of weather modification as weapon.
Considering all works good, the ecological imbalance this would create becomes a paradox. As discovered earlier, the atmosphere is too sensitive to tiny influences; then imagining the extent to which massive changes like alteration in the course of a hurricane might result in, really leaves behind a greatly dreadful picture.
The very prophylactic measure could leave us in trepidation.