On the relative absorption strengths of water vapour in the  blue wavelength range

Lampel, Johannes; Pöhler, Denis; Tschritter, J.; Frieß, Udo; Platt, U.

doi:10.5194/amt-8-4329-2015

Cited by 37 publications

(74 citation statements)

References 67 publications

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“…Furthermore, the 430-480 nm retrieval window used by Wang et al (2014) contains both the 7ν (435-450 nm) and the 6ν +δ (460-480 nm) spectral bands of water vapor. Lampel et al (2015) derived scaling factors for the water vapor absorption bands in the blue spectral range using the 7ν band as a reference. They suggested that the absorption strength of the 6ν + δ band should be scaled by a factor of 1.02 ± 0.07 in HITRAN 2008 (Rothman et al, 2009).…”

Section: Omi and Ssmismentioning

confidence: 99%

Validation and update of OMI Total Column Water Vapor product

Wang¹,

Abad²,

Liu³

et al. 2016

Atmos. Chem. Phys.

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Abstract. The collection 3 Ozone Monitoring Instrument (OMI) Total Column Water Vapor (TCWV) data generated by the Smithsonian Astrophysical Observatory's (SAO) algorithm version 1.0 and archived at the Aura Validation Data Center (AVDC) are compared with NCAR's ground-based GPS data, AERONET's sun-photometer data, and Remote Sensing System's (RSS) SSMIS data. Results show that the OMI data track the seasonal and interannual variability of TCWV for a wide range of climate regimes. During the period from 2005 to 2009, the mean OMI−GPS over land is −0.3 mm and the mean OMI−AERONET over land is 0 mm. For July 2005, the mean OMI−SSMIS over the ocean is −4.3 mm. The better agreement over land than over the ocean is corroborated by the smaller fitting residuals over land and suggests that liquid water is a key factor for the fitting quality over the ocean in the version 1.0 retrieval algorithm. We find that the influence of liquid water is reduced using a shorter optimized retrieval window of 427.7-465 nm. As a result, the TCWV retrieved with the new algorithm increases significantly over the ocean and only slightly over land. We have also made several updates to the air mass factor (AMF) calculation. The updated version 2.1 retrieval algorithm improves the land/ocean consistency and the overall quality of the OMI TCWV data set. The version 2.1 OMI data largely eliminate the low bias of the version 1.0 OMI data over the ocean and are 1.5 mm higher than RSS's "clear" sky SSMIS data in July 2005. Over the ocean, the mean of version 2.1 OMI−GlobVapour is 1 mm for July 2005 and 0 mm for January 2005. Over land, the version 2.1 OMI data are about 1 mm higher than GlobVapour when TCWV < 15 mm and about 1 mm lower when TCWV > 15 mm.

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Section: Omi and Ssmismentioning

confidence: 99%

Validation and update of OMI Total Column Water Vapor product

Wang¹,

Abad²,

Liu³

et al. 2016

Atmos. Chem. Phys.

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“…We suggest addressing at the same time uncertainties in recent water vapour absorption cross sections (see e.g. Lampel et al, 2015b;Volkamer et al, 2015;Wilson et al, 2016 andLampel et al, 2017a) at around 419 and 360 nm in a controlled laboratory environment with wellknown light path lengths at different pressure and humidity values. The availability of such a data set has the potential to improve the spectral retrieval of various trace gases substantially as pointed out below.…”

Section: Discussionmentioning

confidence: 99%

“…From MAX-DOAS and LP-DOAS observations it was reported that these absorption lines are overestimated by a factor of 2 in HITRAN2012 (Lampel et al, 2015b), while the overall shape is relatively well reproduced. Thus the water vapour absorption contains some uncertainty, which could have an effect on the detection of the O 4 absorption band at 419 nm.…”

Section: Absorption Band At 419 Nmmentioning

confidence: 99%

“…Additionally, their absorption cross sections may not be known precisely enough (e.g. water vapour; Lampel et al, 2015bLampel et al, , 2017a to determine their abundances in other spectral ranges and thus constrain their overall absorption in order to obtain an extended O 4 absorption cross section from MAX-DOAS or LP-DOAS field measurements. Dedicated laboratory studies will be needed.…”

Section: Hypothetical O 4 Absorption Cross Sectionsmentioning

confidence: 99%

“…However, this spectral region is also known for uncertainties of the available water vapour cross section as reported in Lampel et al (2015b), which overlays potential O 4 absorptions. Using the same ratio of peak absorption cross sections of O 4 at 477 and 446 nm, an absorption band at 419 nm could potentially have a peak optical depth (OD) of 2 × 10 −4…”

Section: Introductionmentioning

confidence: 99%

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Detection of O<sub>4</sub> absorption around 328 and 419 nm in measured atmospheric absorption spectra

et al. 2018

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Abstract. Retrieving the column of an absorbing trace gas from spectral data requires that all absorbers in the corresponding wavelength range are sufficiently well known. This is especially important for the retrieval of weak absorbers, whose absorptions are often in the 10 −4 range. Previous publications on the absorptions of the oxygen dimer O 2 -O 2 (or short: O 4 ) list absorption peaks at 328 and 419 nm, for which no spectrally resolved literature cross sections are available. As these absorptions potentially influence the spectral retrieval of various trace gases, such as HCHO, BrO, OClO and IO, their shape and magnitude need to be quantified.We assume that the shape of the absorption peaks at 328 and 419 nm can be approximated by their respective neighbouring absorption peaks. Using this approach we obtain estimates for the wavelength of the absorption and its magnitude. Using long-path differential optical absorption spectroscopy (LP-DOAS) observations and multiaxis DOAS (MAX-DOAS) observations, we estimate the peak absorption cross sections of O 4 to be (1.96 ± 0.20) × 10 −47 cm 5 molec −2 and determine the wavelength of its maximum at 328.59 ± 0.15 nm.For the absorption at 419.13 ± 0.42 nm a peak O 4 cross-section value is determined to be (5.0 ± 3.5) × 10 −48 cm 5 molec −2 .

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Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

et al. 2017

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Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible‐light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible‐light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800–900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high‐temperature volcanic gases. We attribute the high water vapor emissions to a boiling‐off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible‐light DOAS systems could be used to measure water vapor emissions at numerous other high‐elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

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On the relative absorption strengths of water vapour in the blue wavelength range

Cited by 37 publications

References 67 publications

Validation and update of OMI Total Column Water Vapor product

Validation and update of OMI Total Column Water Vapor product

Detection of O<sub>4</sub> absorption around 328 and 419 nm in measured atmospheric absorption spectra

Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

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On the relative absorption strengths of water vapour in the blue wavelength range

Cited by 37 publications

References 67 publications

Validation and update of OMI Total Column Water Vapor product

Validation and update of OMI Total Column Water Vapor product

Detection of O&lt;sub&gt;4&lt;/sub&gt; absorption around 328 and 419 nm in measured atmospheric absorption spectra

Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

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Detection of O<sub>4</sub> absorption around 328 and 419 nm in measured atmospheric absorption spectra