GONG/LE Status

 The LE GONG station was shut down on March 25th in anticipation of the arrival of Tropical Cyclone Narelle. TC Narelle made landfall near Exmouth at approximately 8am on March 27th at a Category 4 level with wind speeds between 160–199 km/h. An electrician was able to visit the site, and power was restored to the shelter on April 2nd. We are awaiting word as to when the internet connection to the LSO will be restored.

 One of the first reports from the LSO staff reads:

"Unfortunately, the damage to Exmouth and Learmonth is significant. The road was closed for days due to flooding and the airport across the road is closed for the foreseeable future due to extensive damage to the terminal.

We were able to access the site for the first time yesterday (March 31st) and inspected the GONG shelter. The shelter and turret appear to be unscathed (no obvious wind damage or impacts) but one of the air-conditioner compressor units has been damaged.

The inside of the shelter was dry (hooray) so we attempted to repower, however the main circuit breaker tripped on both attempts. The metal box surrounding the main circuit board outside was blown open and bent at the hinge, and we suspect water may have gotten in behind it. It's also possible there is water in the light fixtures that may be tripping the circuit breakers.

We are also experiencing a site-wide internet outage, so no data flow is possible currently anyway. We are investigating with the network provider to find out what kind of infrastructure damage has occurred and ETA for return to service. We will keep you posted on this front too."

 

Does the Solar Tachocline Change with Solar Cycle

 A thin transition layer where the Sun’s rotation changes abruptly — the outer convection zone rotates differentially, while the inner radiative zone rotates almost like a solid body- is termed as the tachocline similar to the thermocline in oceanic dynamics.  This sharp shear is believed to generate the Sun’s strongest toroidal magnetic fields, which later rise to the surface as sunspots. The tachocline’s  sub-adiabatic stratification allows strong magnetic fields to be stored without immediately rising due to buoyancy. If the solar dynamo exists in the tachocline and generates the magnetic field of the Sun, one would expect solar-cycle related changes in the properties of the tachocline. 

A recent study using three decades of GONG observations reports a secular shift in the tachocline’s position at low latitudes. The analysis also indicates that the tachocline  has been gradually moving closer to the base of the convection zone, indicating that it may be related to the complexity of the solar magnetic field.  

This work is published in Astrophysical journal, 1000, 272 (1000) 2026 April 1. 

Latitude-dependent Time Variations of the Solar Tachocline - IOPscience

Artemis 2 launch and space weather

Artemis II is scheduled to launch tomorrow (April 1, 2026) on a 10-day mission around the Moon. Traveling outside the Earth magnetosphere may pose additional risks from the space weather events (for review of early studies see Chen et al 2024). NOAA Space Weather Prediction Center will provide forecast of space weather conditions for the duration of mission (see article in Space.com), and the NSF's GONG observations will contribute to the modeling. In addition, recent GONG farside images suggest a relatively low level of sunspot activity on a farside of the Sun for the incoming two weeks. 

Solar Activity Report: March 23 -29, 2026

Solar activity during the reporting period ranged from low to moderate levels. The week began with low solar activity and a C3.2 flare was the largest event on March 23 that originated from active region 14392 near the southeast limb. The X‑ray flux generally remained at B‑level until a C7.3 flare was produced on March 24 by an active region rotating onto the Earth‑facing side from behind the northeast limb. This region was later designated NOAA 14403. Following this event, the X‑ray flux stayed within the C‑level range, with several C‑class flares and two M‑class flares. The largest event on March 25 was a C3.7 flare. Activity increased to moderate levels on March 26 with an M3.9 flare from active region 14403 and multiple additional C‑class flares.

On March 27, activity declined again to low levels, with only C‑class flares observed; the largest was a C5.4 event. Activity increased once more on March 28 with a long‑duration M1.3 flare from active region 14405. The week concluded with low activity on March 29, when the largest event was a C2.1 flare. Overall, active region 14405 was the most productive during this period, generating nine C‑class flares and one M‑class flare. Several CMEs were associated with these events, but none had Earth‑directed components.

Status of GONG network: March 27, 2026

 Status of GONG network as of Friday, March 27:

• The Learmonth instrument is down due to passage of a tropical cyclone (see map below showing path of tropical cyclone Narelle 34U, © Bureau of Meteorology) 
• The Udaipur instrument is unreachable (local team was requested to investigate).
• The El Teide instrument is operational, and the sky is clear.
• The Cerro Tololo instrument is operational, and the sky is clear.
• The Big Bear instrument is down for scheduled maintenance. NISP engineering team is on site performing preventive maintenance.
• Road to Mauna Loa Observatory is officially completed. However, it remains closed for general public and non-emergency observatory access.

Solar Activity Report: March 16 - 22, 2026

The week began with moderate solar activity, which declined to low levels by mid‑week and remained low for the rest of the period, with only a slight gradual increase in X‑ray flux intensity that stayed within the B‑class range. Three low‑intensity M‑class flares occurred at the start of the week, one on each of the first three days. The most active day was March 18, when an M2.7 flare was produced, along with C2.7, C2.8, C2.9, and C3.6 flares. Other notable flares include an M2.8 and C5.9 on March 16, an M1.3 on March 17, and a C2.3 on March 19. All of these flares originated in the southern hemisphere, primarily from active region 14392. Two associated CMEs from the March 16 and March 18 M‑class flares arrived simultaneously on March 20.

Helioseismic mapping of the invisible hemisphere indicates that several active regions may rotate onto the Earth‑facing side within the next seven days. One of them is active region 14378, which crossed the west limb and moved to the far side about two weeks ago, has persisted and is expected to reappear at the east limb around March 24. 

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 311,  and  the  p-mode frequency data products for central GONG month 310 is completed and the data products are now available.