Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Boundary clear air echos in southern Sweden
SMHI, Forskningsavdelningen.
2000 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

The C band weather radars of today are sensitive enough to record clear air echos from the boundary layer during the warmer seasons even in latitudes as high as Scandinavia. Such clear air echos have long been recognised in the US and a.o. used to retrieve the wind. Curiously enough, in Europe there has been, and perhaps still is, a wide spread belief among meteorologists that boundary layer clear air echos are absent there. The probable reason is that since European weather radars are almost only used to monitor precipitation, in most countries weak echos, supposed not to represent precipitation, are suppressed. This may be performed in many ways, for instance by using the STC (Sensitivity Time Control, also called Swept Gain) which suppresses echos close to the radar, or by thresholding weak echos in the radar images used. The threshold is usually about 10 dBz, and since most clear air echos are weaker, they do not appear in the images, though the radar rnight have recorded them.

That these clear air echos actually are echos from the air, as from sharp refractive index gradients, insects or birds, is evident since Doppler radars show that they move, generally approximately with the winds recorded by other means. The exceptions are from targets heading towards a specific goal, as rnigrating birds, birds leaving a nocturnal roost and locust swarms.

The concept 'clear air echos' refers to echos from a non-precipitating atmosphere. There is no commonly agreed stringent definition of clear air echos.

sted, utgiver, år, opplag, sider
SMHI , 2000. , s. 22
Serie
RMK, Rapport Meteorologi och Klimatologi, ISSN 0347-2116 ; 92
HSV kategori
Forskningsprogram
Meteorologi; Klimat
Identifikatorer
URN: urn:nbn:se:smhi:diva-2352Lokal ID: Meteorologi, Rapporter, Serie RMKOAI: oai:DiVA.org:smhi-2352DiVA, id: diva2:947645
Tilgjengelig fra: 2000-05-13 Laget: 2016-07-08 Sist oppdatert: 2019-06-13bibliografisk kontrollert

Open Access i DiVA

fulltext(5165 kB)3 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 5165 kBChecksum SHA-512
a9d720aa23ef5bdf5879b19b3cfee352ca441130cc21d44e03e68e52d6d8c1e998458f38c93334fc3a7f85b02f317e47a35c2395d9f430f0b0cd1154f4cab409
Type fulltextMimetype application/pdf

Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 3 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

urn-nbn

Altmetric

urn-nbn
Totalt: 27 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.7
|