GRUAN, the Global Climate Observing System (GCOS) Reference Upper Air Network, is an international reference observing network of sites measuring essential climate variables above Earth's surface, designed to fill an important gap in the current global observing system. GRUAN’s objectives are to (1) provide long-term, high-quality climate records, (2) constrain and calibrate data from more spatially comprehensive global observing systems (including satellites and current radiosonde networks), and (3) fully characterize the properties of the atmospheric column.

Routine radiosonde observations in combination with tethered balloon measurements provided high-resolution profiles of the atmospheric conditions in the column The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC, ) expedition was a one-year-long expedition into the Central Arctic (September 2019 - October 2020). For the first time a modern research icebreaker was able to operate in the direct vicinity of the North Pole year round, including the nearly half year long polar night during winter. In terms of the logistical chal Th…

the behavior of wind and the physical properties of the upper atmosphere, often in order to improve the guidance and control of missiles. Radiosondes The Signal Corps Laboratories (SCL) was a research installation under the command of the U.S. Army Signal Corps. Headquartered at Fort Monmouth, New Jersey, SCL directed research on electronics, radar, and communication systems for the U.S. Army. Throughout its history, SCL operated under many names as the organizational structure of the Signal Corps and the U.S. Army changed over time. The development of new meteorological technologies and techniques have long been a staple function of the Signal Corps and its laboratory installations. Since World War I, the Signal Corps was responsible for reporting the weather and other meteorological information to the Army for the purposes of long-range artillery and antiaircraft support, storm tracking, and general operational planning. In 1929, the Signal Corps oversaw the launch of the first radio-equipped weather balloon at Fort Monmouth. Although SCL lost its official weather reporting and forecasting duties to the U.S. Army Air Corps in 1937, the laboratories retained their responsibility for the development, procurement, supply, and maintenance of the Army’s meteorological equipment for decades. While the U.S. Air Force provided the Army with operational weather support, the Signal Corps served as the primary agent for Army meteorological research and development. The varied effects of weather on communications equipment ensured that meteorological activities remained a fundamental component of SCL. At one point during the 1940s, SCL acquired Raytheon Manufacturing Company’s AN/CPS-9 Storm Detection Radar, the first radar system designed specifically for meteorological use. Researchers at Evans Signal Laboratory were tasked with modifying the CPS-9 to suit the needs and requirements of the Army Air Forces (AAF) Weather Service. In 1948, the new weather radar successfully observed a rainstorm from a distance of 185 miles and tracked it as it passed over Fort Monmouth. The modified AN/CPS-9 was brought into service by the AAF Weather Service (redesignated as the Air Weather Service in 1946) in 1954 and installed at military bases around the world. In addition to weather prediction, SCL investigated the behavior of wind and the physical properties of the upper atmosphere, often in order to improve the guidance and control of missiles. Radiosondes equipped to high-altitude balloons were used to measure humidity, temperature, and pressure more than 20 miles high up in the atmosphere. For altitudes above that, SCL researchers in the post-WWII era used rockets to conduct atmospheric studies and collect…