Cryogenic Limb Array Etalon Spectrometer observations of tropical cirrus

Mergenthaler, J. L.; Roche, A. E.; Kumer, J. B.; Ely, G. A.

doi:10.1029/1999jd900397

Cited by 46 publications

(61 citation statements)

References 22 publications

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“…These large optical depths are larger than gas optical depths and enhance 12.1 mm atmospheric limb view radiances. Previous measurements of 12 mm PSC emission by ISAMS and CLAES [Taylor et al, 1994;Massie et al, 1994] and of subvisible cirrus by CLAES [Mergenthaler et al, 1999] confirm this simple physics.…”

Section: Introductionsupporting

confidence: 62%

“…Thin cirrus is commonly referred to as ''subvisible'' cirrus, since the human eye, looking upward, cannot detect these optically thin clouds. Cirrus extinctions near the tropopause were measured by CLAES [Mergenthaler et al, 1999] Gille et al, submitted manuscript, 2007) joins the roster of space experiments which can measure clouds in the stratosphere and upper troposphere. HIRDLS is a limb viewing emission experiment with 21 spectral channels in the infrared, spanning the wavelength range from 6.2 to 17.2 mm, and was designed to measure temperature-pressure profiles, the mixing ratios of many gas species (i.e., O 3 , HNO 3 , H 2 O, NO 2 , N 2 O, CH 4 , CFC-11, CFC-12, ClONO 2 , N 2 O 5 ), and cloud/ aerosol extinction profiles.…”

Section: Introductionmentioning

confidence: 99%

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High Resolution Dynamics Limb Sounder observations of polar stratospheric clouds and subvisible cirrus

et al. 2007

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Section: Introductionsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

High Resolution Dynamics Limb Sounder observations of polar stratospheric clouds and subvisible cirrus

et al. 2007

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“…Here we argue that infrared (IR) limb sounding from space provides an alternative measurement technique of high sensitivity for the detection of optically thin clouds (Mergenthaler et al, 1999;Massie et al, 2007;Griessbach et al, 2014), subvisible cirrus (SVC) defined by the extinction range 2 × 10 −4 -2 × 10 −2 km −1 (Sassen et al, 1989), or the even thinner ultra-thin tropical cirrus (UTTC) Luo et al, 2003). The IR limb sounder detection sensitivity for clouds is in the range of spaceborne lidar measurements (Höpfner et al, 2009;Spang et al, 2012).…”

Section: R Spang Et Al: Satellite Observations Of Cirrus Clouds In mentioning

confidence: 99%

Satellite observations of cirrus clouds in the Northern Hemisphere lowermost stratosphere

Spang¹,

Günther²,

Riese³

et al. 2015

Atmos. Chem. Phys.

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Abstract.Here we present observations of the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) of cirrus cloud and water vapour in August 1997 in the upper troposphere and lower stratosphere (UTLS). The observations indicate a considerable flux of moisture from the upper tropical troposphere into the extratropical lowermost stratosphere (LMS), resulting in the occurrence of highaltitude optically thin cirrus clouds in the LMS.The locations of the LMS cloud events observed by CRISTA are consistent with the tropopause height determined from coinciding radiosonde data. For a hemispheric analysis in tropopause relative coordinates an improved tropopause determination has been applied to the European Centre for Medium-Range Weather Forecasts (ECMWF) temperature profiles. We found that a significant fraction of the cloud occurrences in the tropopause region are located in the LMS, even if a conservative overestimate of the cloud top height (CTH) determination by CRISTA of 500 m is assumed. The results show rather high occurrence frequencies ( ∼ 5 %) up to high northern latitudes (70 • N) and altitudes well above the tropopause (> 500 m at ∼ 350 K and above) in large areas at mid-and high latitudes.Comparisons with model runs of the Chemical Lagrangian Model of the Stratosphere (CLaMS) over the CRISTA period show a reasonable consistency in the retrieved cloud pattern. For this purpose a limb ray tracing approach was applied through the 3-D model fields to obtain integrated measurement information through the atmosphere along the limb path of the instrument. The simplified cirrus scheme implemented in CLaMS seems to cause a systematic underestimation in the CTH occurrence frequencies in the LMS with respect to the observations. The observations together with the model results demonstrate the importance of isentropic, quasi-horizontal transport of water vapour from the subtropics and the potential for the occurrence of cirrus clouds in the lowermost stratosphere and tropopause region.

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“…Previous studies examining the effects of El Nino on upper tropospheric cirrus have based their results on observations by satellites from space (Wang et al, 1996;Mergenthaler et al, 1999;Sandor et al, 2000;Massie et al, 2000;Cess et al 2001). Massie et al (2000) analysed geographical distributions of aerosol extinction data in the troposphere and stratosphere for 1993-1998 from the Halogen Occultation Experiment (HALOE) and showed that during El Nino conditions of 1997 upper tropospheric cirrus increased over the mid-Pacific and decreased over Indonesia.…”

Section: Introductionmentioning

confidence: 99%

A study on natural and manmade global interannual fluctuations of cirrus cloud cover for the period 1984–2004

et al. 2007

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Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period . CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to −0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ∼2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about −0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid-latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends Correspondence to: K. Eleftheratos (kelef@geol.uoa.gr) over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

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Cryogenic Limb Array Etalon Spectrometer observations of tropical cirrus

Cited by 46 publications

References 22 publications

High Resolution Dynamics Limb Sounder observations of polar stratospheric clouds and subvisible cirrus

High Resolution Dynamics Limb Sounder observations of polar stratospheric clouds and subvisible cirrus

Satellite observations of cirrus clouds in the Northern Hemisphere lowermost stratosphere

A study on natural and manmade global interannual fluctuations of cirrus cloud cover for the period 1984–2004

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