Hurricane Maria from Satellite (Elizabeth Dahl)

Introduction

Hurricane Maria was a Category 5 hurricane that affected Puerto Rico from September 16-24, 2017. The hurricane was deadly and is regarded as the worst natural disaster to affect the Caribbean in recorded history. In this lab, we will be analyzing the event from satellite imagery to better understand its formation and structure.

Figure 1: Visible satellite imagery of Hurricane Maria from NASA Worldview. September 16-24, 2017.

Figure 1 is a visible satellite image of Hurricane Maria from September 16-24, 2017. The storm started southeast of Puerto Rico and had a northwest path through the Atlantic. The storm eventually reached North America and affected the east coast, but we will be focusing on its effects in Puerto Rico. The hurricane has a clear cyclonic structure and a large spatial scale. 

Satellite Analysis

To get a better understanding of the hurricane, we can look at the cloud top height, shown in Figure 2a. Though data was not available for the entire spatial scale of the hurricane, we can still get valuable information from data available for the outskirts of the hurricane. On the west side of the cyclone, cloud top heights are about 13-15+ km. This is to be expected from a hurricane because of how deep the clouds are and the instability associated with them, which allows for air to rise higher.

Figure 2a: Cloud top height satellite data from 9/16/17.

Figure 2b: Cloud top height color bar

Next, looking at cloud top temperature in Figure 3a, we can see that the cloud top temperature over the hurricane. Cloud top temperatures of the cyclone are about 150K, while temperatures outside of the cyclone are as high as 350K. Cloud top temperatures are colder in regions with higher cloud top heights which is what we would expect. The stark contrast between the cyclone's cloud temperatures and the surrounding clouds is also stark, and of note.

Figure 3a: Cloud top temperature satellite data from 9/16/17.

Figure 3b: Cloud top temperature color bar

Lastly, we will look at precipitation rates during Hurricane Maria. Figure 4a shows precipitation rate from satellite data on 9/16/17. The highest precipitation rates are at the center of the hurricane, with high rain rates of over 40 mm/hr. The rain rate decreases to the edges of the hurricane, with the lowest values on the outskirts of the hurricane at about 0.1 mm/hr. This high rain rate in the center of the hurricane devastated Puerto Rico and the associated flooding was one of the reasons this storm was so disastrous for the island. 

Figure 4a: Precipitation rate satellite data from 9/16/17.

Figure 4b: Precipitation rate color bar