GONG/TD is down for Inclement weather

Photo courtesy Pere L. Palle  

Local support team at Teide Observatory, Tenerife, Canary Islands reports that storm "Emilia" reached the islands 24 hours earlier than expected. The storm brought severe and unusual weather conditions to Tenerife, including strong winds, heavy rain, and a rare form of soft hail known as graupel. The observatory will remain closed until the weather improves. 

GONG/LE: Radiometer/Pyranometer Outage

 The local Corella (Australian white cockatoos) have been up to their usual antics, and have once again chewed through the cable from the radiometer. The outage started on 11/12/25. Radiometer data will return after repair parts have been shipped from Boulder HQ to Learmonth.

 

GONG/ML: Shelter Condition

 NOAA/GML staff have provided the project with some recent pictures (12/3/25) of the shelter. The GONG engineering staff is working on plans to get the shelter painted during the restart after the access road and power to the site have been established. (Photos: Paul Fukumura-Sawada, NOAA)

 

UPDATE: Mauna Loa Access Road

 NOAA/GML and the US DOT met the week of 12/1. The road construction contractor is pushing to get the project done as quickly as possible, and plan to have the work completed within the current period of performance that expires on March 31st.

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 308, and the p-mode frequency data products for central GONG month 307 is completed and the data products are now available.

Why Active Regions Appeared Displaced in GONG Far-Side Map Compared to Mars Rover View

 

In two recent posts, we compared an image of the Sun’s far side taken by the Mars rover with the GONG far-side helioseismic map. A large active region is clearly visible in both, though at different apparent locations. This displacement arises solely from differences in viewing geometry. The rover observes the Sun’s far side with distinct values of B0 and L0, which differ from those used in the helioseismic map, and the discrepancies we note result from the combined influence of these parameters. Variations in L0 are driven by the rover’s position in the orbit, which changes over time. 

As mentioned earlier, the rover will provide far-side observations for only the next two months. During this period, its viewing angle will gradually shift, yielding perspectives of different portions of the Sun’s far side. Since Mars completes an orbit around the Sun in about 687 days, the Sun's far side can be observed from Mars roughly every other year, with each transit lasting about two months as determined by its orbital velocity.

Expect a moderate geomagnetic storm and aurora on 5-6 Dec.

A large coronal hole that we wrote about in our post from 7 Nov.  (also see an early post on 14 Sep.) is again crossing the solar central meridian. Image on the left taken by AIA instrument on board NASA's Solar Dynamics Observatory shows the coronal hole early 2 December 2025 (universal time). This coronal hole developed at the end of April, 2025 (8 months ago!) and since then was steadily growing. The coronal hole coincides with a large area of weak unipolar magnetic field of mostly negative polarity (right panel, see white outline  plotted over a magnetogram taken by GONG station at Learmonth, Australia). The magnetic field from this area opens up to the interplanetary space forming a high speed solar wind stream. One should expect that in about 4 days (5-6 Dec), the solar wind from this stream will intersect with Earth's magnetosphere and cause a moderate geomagnetic storm and aurora.