MQTT AWS example , how to derive the value of temperature

Hi everyone , i have been studying on the connection to aws via MQTT lately , upon Establishing a conenction to aws  and keyed in "demo start", the console start generating an output with temperature value as shown below

from S5D9 user manual i read that the adc converted the output voltage that is  directly proportional to the die temperature generated from the on chip temperature sensor .hence i got a few question

1)Is it possible that the die temperature is as low as the temperature shown in the console?

2)How did the ADC do the conversion

3)Why is the value decreasing

will be glad if any experts out there can help!

Regards 

Qw