Maximum usable frequency and skip distance maps over Italy

Abstract

Since 1988 the Upper Atmosphere Physics unit of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) has provided maps of Maximum Usable Frequency (MUF) and skip distance over a European area extending in latitude from 34°N to 60°N and in longitude from 5°W to 40°E. Anyhow, these maps suffer the following restrictions: (1) they are provided with two months in advance and so they are not suitable for space weather purposes; (2) they are represented with few isolines; (3) they are centred only on Rome (41.8°N, 12.5°E) and generated in black and white; (4) MUF are calculated with a really simple algorithm. In order to overcome these restrictions, a new software tool was developed to get climatological maps (up to three months in advance) and quasi real-time maps, (nowcasting) limited to the sector extending in latitude from 34°N to 48°N and in longitude from 5°E to 20°E, which includes the whole Italian territory. In order to achieve a greater accuracy, MUF and skip distance maps are generated combining the Simplified Ionospheric Regional Model (SIRM) and its UPdated version (SIRMUP) with the Lockwood algorithm. Climatological maps are generated every hour on the basis of the predicted 12-months smoothed sunspots number. Nowcasting maps are generated every 15 min exploiting foF2 and M(3000)F2 data autoscaled at the ionospheric stations of Rome and Gibilmanna (37.6°N, 14.0°E). Nowcasting maps constitute the most important novelty because they let High Frequency (HF) users know in quasi real-time the radio propagation conditions over Italy. This turns out to be very valuable in terms of reliable radio links, especially in case of adverse space weather events.