Longitude

About: Longitude is a research topic. Over the lifetime, 2260 publications have been published within this topic receiving 54988 citations. The topic is also known as: angle of longitude.

Westward shift of western North Pacific tropical cyclogenesis

Abstract: Tropical cyclones (TCs) in the western North Pacific or typhoons account for one third of all TCs in the world and the change of the mean TC genesis location can affect billions of people in Pacific islands and Asian countries. The annual mean TC genesis longitude is generally controlled by the east-west shift of the tropical upper tropospheric trough (TUTT). A pronounced westward shift in the TUTT is found in all of the available reanalysis data sets during 1979–2012, suppressing TC genesis in the eastern portion (east of 145°E) of the western North Pacific basin due to the enhanced vertical wind shear associated with the TUTT shift. As a result, the annual mean TC genesis longitude has significantly shifted westward since 1979. The westward shifting trends in the TUTT and TC genesis are associated with the enhanced tropical tropospheric warming, which is consistent with the response of the tropospheric temperature to global warming.

Reduction of electron temperature in low‐latitude ionosphere at 600 km before and after large earthquakes

Abstract: [1] We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that T e around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80-120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F 2 peak frequency, f o F 2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E-130°E are used together with electron density(N e ), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI T e /N e and ionosonde f o F 2 /h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.