© George Anderson
Farnborough, Hampshire, United Kingdom of Great Britain and Northern Ireland
Latitude: 51° 16' 39'' N
Longitude: 0° 46' 5'' W
22 July 2010 1810 (Local Time)
Camera direction: towards W
Image P/S code: P.13.1.5.1
Image I.D.: 4068
-
Circumzenithal arc
This brightly coloured circumzenithal arc was formed by the refraction of sunlight through the ice crystals of a Cirrus fibratus cloud. The circumzenithal arc is a halo phenomenon that occurs only when the light source (for example, the Sun) is at an elevation of less than 32° above the horizon.
The arc is centred on the zenith - the point of the sky directly above the observer - and so is observed high in the sky. It typically displays bright spectral colours, as shown in this picture. A distinguishing feature is that red is always on the lower, outside of the arc, and violet is always on the upper, inside.
The exact location, length and brightness of the circumzenithal arc all vary with the Sun's elevation. When the elevation is about 22°, the arc touches the large (46°) halo, if it is visible. However, more frequently than not, the large halo is not seen – as in this case.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© George AndersonFarnborough, Hampshire, United Kingdom of Great Britain and Northern IrelandLatitude: 51° 16' 39'' NLongitude: 0° 46' 5'' W22 July 2010 1810 (Local Time)Camera direction: towards WImage P/S code: P.13.1.5.1Image I.D.: 4068
Circumzenithal arc
Circumzenithal arc in Cirrus over Exeter, south-west England, UK. The extension of the arc into apparently clear sky towards the left-hand side suggests the presence of a very thin layer of nearly invisible Cirrostratus covering a wider area than the visible Cirrus fibratus, although a slightly fibrous structure is apparent close to the arc, even in this area. Small patches of Cumulus fractus are visible near the top left- and top right-hand corners of the picture.
Southern England was located to the north of a weak anticyclone centred over the Bay of Biscay. A warm front, associated with a shallow depression in the mid-Atlantic, was encroaching from the west. The Cirrus may have been associated with a thin cloud shield extending well ahead of this warm front.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Matthew ClarkExeter, Devon, United Kingdom of Great Britain and Northern IrelandLatitude: 50° 43' 2'' NLongitude: 3° 31' 56'' W14 June 2008 1740 (Local Time)Image P/S code: S.13.1.5.1Image I.D.: 4135
A complex halo display
This magnificent halo display was formed by the refraction and reflection of sunlight through diamond dust at an altitude of 1 100 m in Neklid, Klinovec, Ore Mountains, Czech Republic.
Such complex displays are usually observed only in polar regions, although they may occasionally occur in mountains when there are ice crystals in the air, as in this case. The dust-like specks in this photograph are in fact the diamond dust ice crystals sparkling in the sunlight.
The halos visible in this picture are: a 22° halo; a parhelic circle and parhelia; a lower tangent arc; infralateral arcs; an upper tangent arc with a suncave Parry arc; a heliac arc; a supralateral arc that touches a circumzenithal arc; and four Tape arcs (also known as 46° Parry arcs).
Some of these halo types are quite common, such as the 22° halo and the parhelia. Others, however, are less frequently seen, and some, such as the heliac arc and Tape arcs, are rarely witnessed.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Claudia HinzNeklid, Klinovec, Czech RepublicLatitude: 50° 24' 12'' NLongitude: 12° 56' 19'' E30 January 2014 1056 (Local Time)Camera direction: towards SSEImage P/S code: P.13.1Image I.D.: 4204
A complex and rare halo display
This is an extreme wide-angle view, looking upwards, of a magnificent halo display formed by the reflection and refraction of sunlight in diamond dust at an altitude of 1 100 m in Neklid, Klinovec, Ore Mountains, Czech Republic.
Diamond dust consists of very small ice crystals in the air which are visible especially when they sparkle in the sunlight. The dust-like specks in this photograph are the diamond dust ice crystals glinting in the sunshine.
Complex halo displays like the one in this picture are usually observed only in polar regions; however, they may occasionally occur in mountains when there are ice crystals in the air.
The halos visible in this picture are, from left to right: a 22° halo; an upper tangent arc; a suncave parry arc; a supralateral arc with left and right upper Tape arcs (also known as 46° Parry arcs); a circumzenithal arc; a heliac arc together with a antisolar (or subanthelic) arc; a Wegener arc; a parhelic circle Tricker arcs; and diffuse antisolar arcs.
Some of these halo types are quite common, such as the 22° halo and circumzenithal arc. Others, however, are less frequently seen, and some, such as the heliac, antisolar, Wegener and Tricker arcs, are rarely witnessed.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Claudia HinzNeklid, Klinovec, Czech RepublicLatitude: 50° 24' 12'' NLongitude: 12° 56' 19'' E30 January 2014 1057 (Local Time)Image P/S code: P.13.1.4.1Image I.D.: 4239
Circumzenithal arc in Cirrus uncinus
The halo phenomenon here is a circumzenithal arc. This formed by the refraction of sunlight through ice crystals in the Cirrus uncinus. There is thin Cirrocumulus at the top of the picture. The thicker patch of Cirrus, near the bottom left, is suggestive of the species spissatus.Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Paulius BeinaraviciusRadikiai, LithuaniaLatitude: 54° 57' 45'' NLongitude: 23° 56' 56'' E05 May 2015 2006 (Local Time)Camera direction: towards WCL = 0, CM = 0, CH = 1Image P/S code: S.13.1.5.1Image I.D.: 4804
Cirrostratus fibratus, circumzenithal arc and supralateral arc
The transparent white cloud is a thin veil of Cirrostratus, which only partly covered the sky. The presence of striations in the cloud suggest the species fibratus. Cirrostratus is composed of ice crystals which often produce halo phenomena, as in this case. The main feature is a strong circumzenithal arc with red colouration on the outside. Below and to the left of this arc is a much fainter supralateral arc extending towards the lower left of the photograph.
A circumzenithal arc will occur only when the light source (for example, the Sun) is at an elevation of less than 32° above the horizon. The circumzenithal arc appears high in the sky and is centred on the zenith, the point of the sky directly above the observer.
A supralateral arc is a rarer and fainter arc of spectral colour that also forms only when the light source is below 32° elevation. The supralateral arc may be mistaken for the 46° halo, but can be distinguished from it by the somewhat brighter and more coloured appearance of the supralateral arc. The apex of the arc is near to or touching the circumzenithal arc.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Frank Le BlancqNoirmont Common, St. Brelade, JerseyLatitude: 49° 10' 18'' NLongitude: 2° 10' 8'' W18 September 2010 1739 (Local Time)Camera direction: towards SWCL = 0, CM = 0, CH = 6Image P/S code: S.13.1.5.1Image I.D.: 4994