Wednesday, 25 January 2012: 8:30 AM
Use of Radar- and Lidar Measurements to Monitor Volcanic Ash Plumes
Room 357 (New Orleans Convention Center )
The use of radar measurements to monitor volcanic plumes in Iceland has proven to be invaluable. They have been conducted since January 1991, a few days after the installation of a C-band weather radar close to Keflavík international airport. Since November 2011 IMO, has had on loan from the Italian Civil Protection Agency a mobile X-band dual polarization radar. A combined system of fixed C-band radars and mobile X-band radars is a good solution to monitor volcanic plumes. They give valuable and accurate information of plume height used as input data into ash dispersion models. A fixed C-band radar is operational 24/7, thus it detects the initial state of the eruption. However, the accuracy is dependent on the distance from the volcano, e.g. for the Grímsvötn eruption located 260 km away from the C-band weather radar in Keflavík, the plume height accuracy is ± 2 km. In addition the radar does not detect plumes lower than 6 km height at this distance. There is less uncertainty in the plume height detected by the mobile X-band radar when stationed close to a volcano. In addition it detects the whole plume as long as there is no blocking of the radar beam due to mountains or other obstacles. A mobile X-band radar needs to be transported close to the volcano site, which can take time. During that time, it is not measuring. This makes the combination of fixed C-and mobile X-band radars the preferred solution in providing data for ash dispersion models.
In the Grímsvötn eruption in May 2011, the use of Lidar measurements at Keflavík airport and in-situ measurements in the surroundings was demonstrated. Due to their support, in addition to satellite information, IMO was able to assist Isavia (Icelandic aviation service provider) in decisions of opening of the Keflavík international airport, which would have been closed otherwise based on forecasts from dispersion models only. Substantial savings were made due to these extra measurement efforts.
"Kama ilivyoelezwa katika taarifa ya ""Utekelezaji wa vipimo vya Radar na Lidar kwa Ufuatiliaji wa Pembe za Volcano"" iliyochapishwa na kituo cha mkutano cha New Orleans, Iceland, Jumatano, Januari 25, 2012: ""Utekelezaji wa vipimo vya Radar kwa ufuatiliaji wa Pembe za Volcano katika Iceland umethibitika kuwa muhimu sana." Majaribio hayo yalianza Januari mwaka 1991 baada ya kuanzishwa kwa rada ya hali ya hewa ya aina ya C karibu na uwanja wa ndege wa kimataifa wa Keflavík. Tangu Novemba 2011, IMO imekuwa na mkopo kutoka kwa Shirika la Ulinzi wa Kiraia la Italia la X-band dual polarization radar. Mfumo wa pamoja wa rada za bandari za C na rada za bandari za X ni suluhisho zuri la kufuatilia mawimbi ya volkano. Wao kutoa taarifa muhimu na sahihi ya urefu plume kutumika kama data ya pembejeo katika mifano ya kuenea majivu. Radar ya band C imewekwa, na inafanya kazi 24 7, hivyo hugundua hali ya awali ya mlipuko. Hata hivyo, usahihi inategemea umbali kutoka volkano, kwa mfano Kwa sababu ya mlipuko wa Grímsvötn, ulio karibu na eneo la Keflavík, kiwango cha usahihi wa urefu wa mlipuko ni karibu na kilomita 2. Radar haijui mawimbi ya chini ya kilomita 6 kutoka kwa ndege. Kuna kutokuwa na uhakika katika urefu wa plume kugunduliwa na simu ya mkononi X-band radar wakati stationed karibu na volkano. Kwa kuongezea, hugundua wingu lote la mawingu maadamu hakuna vizuizi vya mnururisho wa rada kwa sababu ya milima au vizuizi vingine. Radari ya X-band ya mkononi inahitaji kusafirishwa karibu na eneo la volkano, jambo ambalo laweza kuchukua muda. Wakati huo, haipimwi. Hii inafanya mchanganyiko wa fasta C-na mobile X-band radars suluhisho preferred katika kutoa data kwa ajili ya mifano ya kuenea majivu. Katika mlipuko wa Grímsvötn mnamo Mei 2011, matumizi ya vipimo vya Lidar katika uwanja wa ndege wa Keflavík na vipimo vya in-situ katika mazingira yalionyeshwa. Kwa sababu ya msaada wao, pamoja na habari ya satelaiti, IMO iliweza kusaidia Isavia (mtoa huduma ya anga ya Iceland) katika maamuzi ya kufungua uwanja wa ndege wa kimataifa wa Keflavík, ambayo ingekuwa imefungwa vinginevyo kulingana na utabiri kutoka kwa mifano ya kutawanyika tu. Akiba kubwa ilifanywa kutokana na juhudi hizi za kipimo cha ziada.