this presentation is about when the CB clouds are formed

Towering CUmulus

1. THUNDERSTORM

2. Cumulonimbus A cumulus cloud develops upto a great height due to instability and a high degree of humidity in the atmosphere. The release of energy due to over turning of air in the unstable layers give rise to a storm Lightning and thunder Thunderstorms are one or more convective cells in which electrical charges are seen as lightning and thunder.

3. Cumulonimbus High instability in the atmosphere (ELR > DALR) Adequate supply of moisture A triggering mechanism (Local convection (insolation), Orographic lifting, Convergence, Frontal lifting) Low level convergence.

4. Life cycle of a Cumulonimbus Cell Cumulus (Formative) stage Occurs when one or more clouds begin to grow into a large cumulus with a base upto 30km across. Up draught prevails throughout the cell, in which extreme velocities of 100 ft per sec have been reported. Inflow to the cell takes place throughout the sides at all levels through the bottom of the cloud.

5. Life cycle of a Cumulonimbus Cell Mature stage Begins with precipitation. Due to evaporation of the falling drops, the descending air is kept saturated as air warms at the SALR during the descent. Descending air is colder at every stage than the environment and hence continues the downward motion on its own (ELR > SALR)

6. Life cycle of a Cumulonimbus Cell Dissipating stage Downdraught spreads across the lower portion of the cloud and the updraught becomes of secondary importance. Top portion spreading out (appearance of cirrus cloud, false cirrus or anvil cirrus).

7. Simplified model depicting the life cycle of an ordinary Thunderstorm

8. Charging of a Cumulonimbus Cloud Charged cloud particles (through collision and through transfer of ions when a warm hail stone comes in contact with a cold ice crystal). Heavier negatively charged particles end up in lower parts of the cloud with lighter positively charged particles at the top. The charge difference between particles becomes large enough; lightning occurs.

9. The lightning stroke A flow of electrons rushes towards the earth (stepped leader). Movement of positively charged region up into the air through any conducting object such as trees, buildings and even humans. Downward flow of electrons meets the upward surge of positive charge, a strong electric current (bright return stroke) carries positive charge upward into the cloud.

10. Over land, the requisite conditions can be met in various ways: Mountainous regions: Terrain-forced lift can lead to the formation of TCU clouds. Weather fronts: The interaction between warm and cold air masses can create the necessary instability and lift. Dry lines: The boundary between a dry and moist air mass can produce areas of instability, leading to TCU cloud formation. Urban heat islands: Cities can create localized areas of warmth, leading to instability and potentially TCU cloud formation. TCU Cloud formation over land

11. TCU Cloud formation over land While TCU clouds can form over land, they are often:- Less tall and less dense than those that form over ocean waters. More isolated or scattered, rather than forming large clusters. Less likely to develop into severe thunderstorms or tropical cyclones

12. EFFECTS OF SEA STATE ON SENSORS Higher sea state corresponds to better ISAR classification ranges. Small contacts are difficult to be picked up i.e reduced Initial Detection ranges for small contacts. Increasing the threshold can help in sea clutter reduction. EO/ IR ranges may reduce in higher sea states compared to calm sea due to the larger wave heights.

13. EFFECTS OF SEA STATE ON SENSORS Since the buoys are placed under considerable depth, no direct effect of sea state. However sonobuoy position error will increase incase of higher sea state, leading to more error in target tracking. Acoustic Mark On Top (MOT) to update buoy position can be utilized, however it,s a tedious task to update all buoys position using Acoustic MOT