{"id":1145,"date":"2016-10-12T21:51:42","date_gmt":"2016-10-12T21:51:42","guid":{"rendered":"http:\/\/192.168.1.70\/wordpress\/?p=1145"},"modified":"2019-12-08T22:09:40","modified_gmt":"2019-12-08T22:09:40","slug":"vindstig-eda-ms-hvort-skilur-almenningur-betur","status":"publish","type":"post","link":"http:\/\/www.agust.net\/wordpress\/2016\/10\/12\/vindstig-eda-ms-hvort-skilur-almenningur-betur\/","title":{"rendered":"Vindstig e\u00f0a m\/s: Hvort skilur almenningur betur…?"},"content":{"rendered":"
\"haraldur-2\"<\/div>\n
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Getur veri\u00f0 a\u00f0 margir (flestir) hafi litla sem enga tilfinningu fyrir vindstyrk sem gefinn er upp \u00ed metrum \u00e1 sek\u00fandu?<\/strong>\u00a0 Getur veri\u00f0 a\u00f0 flestir skilji mun betur g\u00f6mlu g\u00f3\u00f0u vindstigin?\u00a0 Getur veri\u00f0 a\u00f0 f\u00e6stir geri s\u00e9r grein fyrir a\u00f0 ey\u00f0ileggingam\u00e1ttur vindsins vex mj\u00f6g hratt me\u00f0 vindhra\u00f0anum, miklu hra\u00f0ar en t\u00f6lurnar gefa \u00ed skyn? \u00a0 Getur veri\u00f0 ve\u00f0urfr\u00e9ttir, \u00fear sem vindhra\u00f0inn er gefinn upp sem sek\u00fandumetrar fari meira og minna fyrir ofan gar\u00f0 og ne\u00f0an hj\u00e1 m\u00f6rgum og \u00fea\u00f0 bj\u00f3\u00f0i h\u00e6ttunni heim?<\/span><\/p>\n

\u00cd fersku minni er \u00f3ve\u00f0ri\u00f0 \u00ed september 2012.\u00a0 \u00ddmsir, \u00fear \u00e1 me\u00f0al einn r\u00e1\u00f0herra, t\u00f6ldu a\u00f0 ekki hef\u00f0i veri\u00f0 vara\u00f0 vi\u00f0 ve\u00f0rinu. \u00dea\u00f0 haf\u00f0i \u00fe\u00f3 veri\u00f0 gert, en svo vir\u00f0ist sem \u00fe\u00e6r a\u00f0varanir hafi ekki komist til skila. Hvernig stendur \u00e1 \u00fev\u00ed?<\/strong><\/span><\/p>\n

Haraldur \u00d3lafsson ve\u00f0urfr\u00e6\u00f0ingur kom fram \u00ed sj\u00f3nvarpinu eftir a\u00f0 \u00ed lj\u00f3s kom a\u00f0 \u00d6gmundur r\u00e1\u00f0herra haf\u00f0i ekki skili\u00f0 ve\u00f0urfr\u00e9ttirnar.<\/span>\u00a0 Hann birti<\/a><\/u> ve\u00f0urkort sem s\u00fdnt var \u00ed ve\u00f0urfr\u00e9ttum Sj\u00f3nvarpsins 8. september.\u00a0 \u00dear m\u00e1tti sj\u00e1 a\u00f0 sp\u00e1\u00f0 var um 25 m\/s vindhra\u00f0a skammt nor\u00f0ur af landinu.\u00a0\u00a0 Ve\u00f0urfr\u00e6\u00f0ingurinn t\u00f3k fram a\u00f0 \u00fea\u00f0 jafngilti 10 vindstigum og vi\u00f0 \u00feann vindstyrk rifnu\u00f0u tr\u00e9 upp me\u00f0 r\u00f3tum.\u00a0\u00a0\u00a0 Um lei\u00f0 og hann nefndi 10 vindstig kvikna\u00f0i lj\u00f3s hj\u00e1 m\u00f6rgum.\u00a0N\u00fa loks var tala\u00f0 mannam\u00e1l \u00ed ve\u00f0urfr\u00e9ttunum, en \u00fea\u00f0 haf\u00f0i ekki veri\u00f0 gert \u00e1rum saman.<\/strong>\u00a0 – Loksins.<\/p>\n

\u00dea\u00f0 er nefnilega svo a\u00f0 vi\u00f0 eigum mj\u00f6g g\u00f3\u00f0an skala yfir vindstyrk, skala sem er miklu meira l\u00fdsandi fyrir \u00e1hrif vindsins en sek\u00fandumetrarnir sem \u00ed \u00a0hugum flestra eru bara einhverjar t\u00f6lur, kannski \u00e1l\u00edka t\u00f6lur og hitastigin \u00e1 kortinu.\u00a0\u00a0<\/strong><\/p>\n

\u00dea\u00f0 eru \u00ed raun f\u00e1ir sem gera s\u00e9r grein fyrir hve ey\u00f0ileggingam\u00e1ttur vindsins vex hratt me\u00f0 vindhra\u00f0anum.\u00a0 \u00dea\u00f0 eru f\u00e1ir sem vita a\u00f0 vi\u00f0 tv\u00f6f\u00f6ldun \u00e1 vindhra\u00f0a \u00e1ttfaldast afli\u00f0 \u00ed vindinum.Vindrafst\u00f6\u00f0var framlei\u00f0<\/a>a<\/u> t.d. \u00e1ttfalt meira afl ef vindhra\u00f0inn tv\u00f6faldast, 27 sinnum meira ef hann \u00ferefaldast. \u00a0 \u00a0 Me\u00f0 \u00f6\u00f0rum or\u00f0um, \u00fe\u00e1 er afli\u00f0 \u00ed vindi sem er 24 m\/s n\u00e6stum 30 sinnum meira en afli\u00f0 \u00ed vindi sem er a\u00f0eins 8 m\/s.<\/p>\n

\u00c9g g\u00e6ti vel tr\u00faa\u00f0 \u00fev\u00ed a\u00f0 ve\u00f0urfr\u00e9ttir k\u00e6must mun betur til skila hj\u00e1 flestum ef ve\u00f0urfr\u00e6\u00f0ingar og ve\u00f0urfr\u00e9ttamenn temdu s\u00e9r a\u00f0 nota vindstig \u00e1samt ve\u00f0urheitum frekar en sek\u00fandumetra. \u00a0 E\u00f0a \u00f6llu heldur, nota g\u00f6mlu g\u00f3\u00f0u ve\u00f0urheitin \u00ed sta\u00f0 \u00feeirra \u00feriggja or\u00f0a sem n\u00faor\u00f0i\u00f0 heyrast n\u00e1nast eing\u00f6ngu \u00ed ve\u00f0urfr\u00e9ttum, \u00fe.e. logn, strekkingsvindur og stormur.<\/strong>\u00a0 Ve\u00f0urfr\u00e9ttamenn, a\u00f0 minnsta kost \u00feeir sem komnir eru til vits og \u00e1ra, hlj\u00f3ta a\u00f0 \u00feekkja hin g\u00f6mlu g\u00f3\u00f0u heiti. Til upprifjunar birti \u00e9g h\u00e9r t\u00f6flu sem fengin er a\u00f0 l\u00e1ni h\u00e9r<\/u><\/a> hj\u00e1 Trausta J\u00f3nssyni.<\/span><\/p>\n

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Mat vindhra\u00f0a eftir Beaufort-kvar\u00f0a<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Stig<\/strong><\/td>\nHeiti<\/strong><\/td>\nm\/s<\/strong><\/td>\n\u00c1hrif \u00e1 landi<\/strong><\/td>\n<\/tr>\n
0<\/strong><\/td>\nLogn<\/td>\n0-0,2<\/td>\nLogn, reyk leggur beint upp.<\/td>\n<\/tr>\n
1<\/strong><\/td>\nAndvari<\/td>\n0,3-1,5<\/td>\nVindstefnu m\u00e1 sj\u00e1 af reyk, fl\u00f6gg hreyfast ekki.<\/td>\n<\/tr>\n
2<\/strong><\/td>\nKul<\/td>\n1,6-3,3<\/td>\nVindbl\u00e6r finnst \u00e1 andliti, skrj\u00e1far \u00ed laufi, l\u00edtil fl\u00f6gg b\u00e6rast.<\/td>\n<\/tr>\n
3<\/strong><\/td>\nGola<\/td>\n3,4-5,4<\/td>\nBrei\u00f0ir \u00far l\u00e9ttum fl\u00f6ggum, lauf og sm\u00e1greinar titra.<\/td>\n<\/tr>\n
4<\/strong><\/td>\nStinningsgola<\/td>\n5,5-7,9<\/td>\nLaust ryk og papp\u00edrssneplar taka a\u00f0 fj\u00faka, litlar trj\u00e1greinar b\u00e6rast. Lausamj\u00f6ll byrjar a\u00f0 hreyfast.<\/td>\n<\/tr>\n
5<\/strong><\/td>\nKaldi<\/td>\n8,0-10,7<\/td>\nL\u00edtil lauftr\u00e9 taka a\u00f0 sveigjast. Frey\u00f0andi b\u00e1rur \u00e1 st\u00f6\u00f0uv\u00f6tnum. Lausamj\u00f6ll hreyfist.<\/td>\n<\/tr>\n
6<\/strong><\/td>\nStinningskaldi<\/td>\n10,8-13,8<\/td>\nSt\u00f3rar greinar svigna. Hv\u00edn \u00ed l\u00ednum. Erfitt a\u00f0 nota regnhl\u00edfar. L\u00e1garenningur vi\u00f0varandi.<\/td>\n<\/tr>\n
7<\/strong><\/td>\nAllhvass vindur<\/td>\n13,9-17,1<\/td>\nSt\u00f3r tr\u00e9 sveigjast til. \u00dereytandi a\u00f0 ganga \u00e1 m\u00f3ti vindi. Skyggni sl\u00e6mt \u00ed snj\u00f3komu.<\/td>\n<\/tr>\n
\u00a08<\/strong><\/td>\nHvassvi\u00f0ri<\/td>\n17,2-20,7<\/td>\nTrj\u00e1greinar brotna. Erfitt a\u00f0 ganga \u00e1 m\u00f3ti vindinum. Menn baksa \u00e1 m\u00f3ti vindi. Skyggni \u00ed snj\u00f3komu ver\u00f0ur l\u00edti\u00f0 sem ekkert.<\/td>\n<\/tr>\n
\u00a09<\/strong><\/td>\nStormur<\/td>\n20,8-24,4<\/td>\nL\u00edtilsh\u00e1ttar skemmdir \u00e1 mannvirkjum. Varla h\u00e6gt a\u00f0 r\u00e1\u00f0a s\u00e9r \u00e1 bersv\u00e6\u00f0i. Gl\u00f3rulaus bylur ef snj\u00f3ar.<\/td>\n<\/tr>\n
\u00a010<\/strong><\/td>\nRok<\/td>\n24,5-28,4<\/td>\nFremur sjaldg\u00e6ft \u00ed innsveitum. Tr\u00e9 rifna upp me\u00f0 r\u00f3tum, talsver\u00f0ar skemmdir \u00e1 mannvirkjum.<\/td>\n<\/tr>\n
\u00a011<\/strong><\/td>\nOfsave\u00f0ur<\/td>\n28,5-32,6<\/td>\nMiklar skemmdir \u00e1 mannvirkjum. \u00dativera \u00e1 bersv\u00e6\u00f0i h\u00e6ttuleg. R\u00fdfur hjarn, lyftir m\u00f6l og grj\u00f3ti.<\/td>\n<\/tr>\n
\u00a012<\/strong><\/td>\nF\u00e1rvi\u00f0ri<\/td>\n>= 32,7<\/td>\nAllt lauslegt f\u00fdkur, \u00fear \u00e1 me\u00f0al m\u00f6l og jafnvel st\u00f3rir steinar. Kyrrst\u00e6\u00f0ir b\u00edlar geta olti\u00f0 e\u00f0a foki\u00f0. Heil \u00fe\u00f6k tekur af h\u00fasum. Skyggni oftast takmarka\u00f0, jafnvel \u00ed \u00feurru ve\u00f0ri.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Munur \u00e1 20 m\/s og 30 m\/s hlj\u00f3mar ekki mikill (50%), en \u00fea\u00f0 er samt gr\u00ed\u00f0arlegur munur \u00e1 hvassvi\u00f0ri (20 m\/s, 8 vindstig) og ofsave\u00f0ri (30 m\/s, 11 vindstig).\u00a0\u00a0\u00a0\u00a0 L\u00edklega er \u00fea\u00f0 nokku\u00f0 sem f\u00f3lk gerir s\u00e9r almennt ekki grein fyrir. \u00deetta er einmitt kosturinn vi\u00f0 vindstigin, tilfinningin fyrir \u00e1hrifum vindsins eru meiri.<\/span><\/p>\n

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Vindhra\u00f0atafla Beaufort-kvar\u00f0ans er fr\u00e1 1903, \u00fe\u00e1 var eftirfarandi jafna l\u00f6g\u00f0 til grundvallar:<\/p>\n

V = 0,836 x B3\/2<\/sup> gefur vindhra\u00f0a \u00ed metrum \u00e1 sek\u00fandu\u00a0vi\u00f0 mi\u00f0gildi vindstigsins.<\/span><\/p>\n


\n<\/span>
\n \u00deess m\u00e1 geta a\u00f0 Trausti \u00a0J\u00f3nsson minnist h\u00e9r<\/u><\/a> \u00e1 J\u00f3n \u00d3lafsson langafa bloggarans og skrifar:<\/span><\/p>\n

“J\u00f3n ritstj\u00f3ri \u00d3lafsson<\/span><\/h2>\n

\u00deegar sendingar ve\u00f0urskeyta h\u00f3fust h\u00e9\u00f0an \u00e1ri\u00f0 1906 f\u00f3r fr\u00e9ttabla\u00f0i\u00f0 Reykjav\u00edk (undir ritstj\u00f3rn J\u00f3ns \u00d3lafssonar) flj\u00f3tlega a\u00f0 birta ve\u00f0urskeyti fr\u00e1 nokkrum ve\u00f0urst\u00f6\u00f0vum. \u00dear fylgdu me\u00f0 n\u00f6fn \u00e1 hinum 13 stigum Beaufort-kvar\u00f0ans. L\u00edklegt er a\u00f0 J\u00f3n hafi sj\u00e1lfur ra\u00f0a\u00f0 n\u00f6fnunum \u00e1 kvar\u00f0ann:<\/span><\/p>\n