Two Low Pressure Systems, Northeastern Pacific


From the six trapezoidal windows in the International Space Station (ISS) cupola, astronauts have a field of view stretching as much as 1,000 miles (1,600 kilometers). The cupola is a panoramic control center for the ISS—a dome-shaped module with windows for observing and guiding robotic operations outside of the station. The 360-degree view also allows for observing the Earth and celestial bodies.

In these astronaut photographs from the cupola—taken one minute and thirteen seconds apart on March 20, 2011—two distinct cyclonic vortices whirl within an area of low pressure that spanned the Pacific coast from southern California to Vancouver Island. Part of one of the ISS solar arrays also is visible at image upper left in both images.

The vortices indicate the positions of two storm systems located within a broad area of low pressure over the northeastern Pacific Ocean. Through a process known as cyclogenesis, rotating cyclonic weather systems develop, mature, and dissipate along the frontal zones between different air masses. The smaller of the two systems (upper image) displays a dense cloud pattern and arcing band of a cold front extending from the center of a young, maturing cyclone. The diffuse cloud pattern of the larger system (middle image) indicates an older, dissipating system. The accompanying Geostationary Operational Environment Satellite (GOES-11) image illustrates the relative positions of both storm systems.

Astronaut photographs ISS027-E-6501 (Image A) and ISS027-E-6500 (Image B) were acquired on March 20, 2011, with a Nikon D3S digital camera using a 16 mm lens, and are provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The GOES-11 image was acquired on March 20, 2011, and obtained from the NOAA Geostationary Satellite Server. The astronaut images were taken by the Expedition 27 crew. The images have been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Susan K. Runco and Michael H. Trenchard, NASA-JSC.