Thursday, September 7, 2017

How to Track A Hurricane

The hurricane Harvey made fall in Texas on Friday, August 26, 2017. The other hurricane Irma is coming and predicted will reach Florida on Sunday, September 10, 2017. According to National Hurricane Center, hurricane Irma is extremely dangerous because it is a category 5 storm.  Therefore tracking a hurricane path and predict its movement is very important, so every effort can be prepared to mitigate the disaster. Fortunately, with technology available today we are able to track a hurricane that approaching a land. There are at least two technologies that we can use to track a hurricane, using satellite and radar.

Tracking Hurricane with Satellite

Hurricane can be tracked from atmospheric activity condition, and it is possible using satellite imagery.  From satellite imagery, can be seen atmospheric condition and pattern that shows a hurricane. Geostationary Operational Environmental Satellite (GOES) is a satellite for weather forecasting, severe storm tracking, and meteorology research,  which is operated by National Oceanic and Atmospheric Administration (NOAA). Using the imagery from GOES satellite, we can track a hurricane and its movement. The latest image of the satellite can be accessed via National Hurricane Center Satellite Page and updated every 30 minutes. Figure 1 and 2 below is the latest image of GEOS satellite for Atlantic view and Pacific View. So, if we refresh this page every 30 minutes we will get the latest image, and if there is a hurricane we can track the path. Beside the latest image, other images can be downloaded with File Transfer Protocol (FTP) at this page. Another option to see the GOES satellite image from this website.

The Latest GOES Image for Atlantic view. Updated every 30 minutes
Figure 1. The Latest GOES Image for Atlantic view. Updated every 30 minutes (Source: National Hurricane Center)

The Latest GOES Image for Pacific view. Updated every 30 minutes
Figure 2. The Latest GOES Image for Pacific view. Updated every 30 minutes (Source: National Hurricane Center)
Figure 3 shows the hurricane Irma track path on September 6, 2017 from 8.45 until 15.15 UTC time. Can be seen from the track time lapse the Hurricane  Irma was approaching Puerto Rico Island.

The Hurricane Irma track time lapse on September 6, 2017 from 8.15-15.15 UTC Time
Figure 3. The Hurricane Irma track time lapse on September 6, 2017 from 8.15-15.15 UTC Time

Tracking Hurricane with Radar

Radar can be used to track a hurricane by measuring precipitation reflectivity. In the US, The National Weather Service (NWS) operating Next Generation Radar (NEXTRAD) which consist of 159 high-resolution S-band Doppler weather radars. NEXTRAD detects atmospheric movement (wind) and precipitation. Then the data is presenting in a mosaic map that shows the pattern of precipitation and its movement. NEXTRAD can be used to track the hurricane path almost in real time and can be used as  early warning system to evacuate residence before a storm hit an area. Unlike the satellite imagery with has a large scope, radar data operates using radio wave with a narrow scope compare to satellite, but it is almost real time, so a hurricane can be tracked almost at any time.

The radar data from NEXTRAD is published publicly and can be accessed  via Unidata Internet Data Distribution (IDD).  IDD is a community over 250 universities that disseminate near real time earth observation via internet, as soon as a dataset available from the observing system. Iowa Environmental Mesonet (IEM) of Iowa University is a member of IDD's community. IEM accessed the radar data of NEXTRAD from IDD every five minutes. The radar data from IEM available in raster format (PNG and Geotiff) and also can be accessed via WMS-T service. Please refer to this post to see how to access data via WMS-T service. Figure 4 shows the Hurricane Harvey path time lapse that was tracked from radar data.

The Hurricane Harvey path time lapse
Figure 4. The Hurricane Harvey path time lapse
As a human there is nothing we can do to prevent a hurricane to come, cause we can not control it. But with technologies that available today we can monitor and track it in order to mitigate the impact. 

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