HAMNET Report 13th December 2020

The Global Disaster Alert and Coordination System has reported that a magnitude 6.2 earthquake struck the North-Eastern tip of Taiwan at 13h00 UTC on Thursday the 10th, exposing 10 million people within 100km of the epicenter to risk. Fortunately that epicenter was 74km deep, and so far, no major news of structural damage is seeping out, so hopefully loss of life was also kept to a minimum.

The ARRL has announced the publication of the third edition of Storm Spotting and Amateur Radio. Storm spotting gives radio amateurs another way to offer a public service by using their skills as communicators. In an average year, the US experiences more than 10,000 severe thunderstorms, 5,000 floods, and more than 1,000 tornadoes. During these weather events, ham radio volunteers provide real-time information to partners such as emergency managers and National Weather Service forecasters.

New in this 3rd edition are lessons learned and response reports from the 2017 hurricane season, among other things. Co-authors are University of Mississippi Professor of Emergency Management Michael Corey, KI1U, and former Embry Riddle Aeronautical University meteorology professor Victor Morris, AH6WX, with Contributing Editor Rob Macedo, KD1CY.

The ARRL also reports that the world’s largest solar observatory, National Science Foundation (NSF) Daniel K. Inouye Solar Telescope in Hawaii, has released its first image of a sunspot, capturing the phenomenon in striking detail. The image, taken last January, is among the first solar images of the new Solar Cycle 25. The telescope’s 4-meter primary mirror will give the best views of the sun from Earth throughout Solar Cycle 25. The image was released along with the first of a series of Inouye-related articles featured in the Solar Physics journal. As radio amateurs know, sunspots and other solar activity can affect HF radio propagation, among other things, and they are where coronal mass ejections (CMEs) and solar flares originate. The Inouye telescope is in its final stages of construction.

“While the start of telescope operations has been slightly delayed due to the impacts of the COVID-19 global pandemic, this image represents an early preview of the unprecedented capabilities that the facility will bring to bear on our understanding of the sun,” said David Boboltz, NSF Inouye Solar Telescope Program Director. Solar Cycle 25 is predicted to peak in mid-2025.

“With this solar cycle just beginning, we also enter the era of the Inouye Solar Telescope,” said Matt Mountain, President of the Association of Universities for Research in Astronomy (AURA), the organization that manages the National Solar Observatory and the Inouye Solar Telescope. “We can now point the world’s most advanced solar telescope at the sun to capture and share incredibly detailed images and add to our scientific insights about the sun’s activity.”

Thanks to the ARRL letter of 10th December for both these extracts.

Anette Jacobs ZR6D sent me a report issued by Santjie White, she of the Aeronautical Rescue Coordination Centre, describing Exercise Malperd, held last Saturday the 5th December. Santjie writes:

The ARCC and HAMNET worked together to organize an aeronautically themed training exercise on the East Rand today (Saturday). The exercise was a great success with many lessons identified and training scenarios tested.

The success of the exercise would not have been possible without the dedication and collaboration of all the Search and Rescue units and organizations that worked together. The Search and Rescue units and organizations consisted of state and private companies as well as volunteers from the various SAR institutions.

The ARCC thanks every single member involved in the events of the day, and their families for allowing them to join in the training over the weekend.

Santjie expressed her thanks and extreme gratitude to the members and organizations for attending and making available resources at their own costs, all for developing and maintaining a world class SAR service to our aviation community.

Thank you, Anette, for providing me with that news.

Carolyn Gramling, writing in Science News says that Atlantic hurricanes are taking longer to weaken after making landfall than they did 50 years ago, thanks to climate change. Over the past 50 years, increasingly warm ocean waters have juiced up the storms, giving them more staying power after they roar ashore, scientists report in Nature of November 12th. That could potentially extend storms’ destructive power farther inland, the researchers say.

As ocean waters warm, tropical cyclones — called hurricanes in the Atlantic Ocean — are likely to gain in intensity, studies show. They can also hold more moisture, leading to seemingly unremitting rainfall. And they may move more slowly, allowing more time to dump that rain on coastal communities. All of this increases the potential hazard on land.

Once a storm hits land, its energy begins to dissipate. But that relief is coming later than it once did, report physicists Lin Li and Pinaki Chakraborty, both of the Okinawa Institute of Science and Technology in Japan.

Li and Chakraborty analysed the intensity of historical Atlantic hurricanes over the first 24 hours after landfall. In 1967, a typical storm’s intensity decayed by 76 percent within the first day after landfall. But by 2018, storms were only 52 percent less intense after 24 hours. That trend, the researchers say, aligns with increasing sea-surface temperatures in the Gulf of Mexico and the western Caribbean Sea.

That’s because the intense winds of cyclones feed on moisture and heat picked up from the warm waters, and warmer air can also hold more moisture. So as the oceans heat up, they not only add more moisture, making hurricanes rainier, but also add more heat — like a portable engine the storm uses to fuel its fury for just a bit longer.

In another article on the same website, Carolyn says that once Antarctic ice melting, as a result of the warmer waters, reaches a certain threshold, reversal of the trend will not be possible, and the melting cannot then be undone.

This will lead to a progressive rise in sea level of up to 50 metres in the next few centuries, if all the ice over Antarctica were to melt. The flat plain that is the Cape Peninsula would mostly disappear, and Table Mountain would become an island, disconnected from the rest of the Cape. Quite a thought, isn’t it?

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.