1 DO NOT USE Tephigram for this question) A layer of dry atmosphere is initially 100 hPa thick and has a potential temperature of 290 K at 600 hPa and 294 K at 500 hPa. If this layer, preserving its mass and pressure difference of 100 hPa, sinks adiabatically to 900 and 800 hPa, (a) what are the temperatures at the top () and the bottom () of the layer before AND after the sinking? (b) Find the lapse rate, defined as = (Ttop - Tbottom)/z (in degrees per metre), before AND after the sinking. In the definition, z is the depth of the layer (in metres)