Validation of FORMOSAT-3/COSMIC level 2 &amp;quot;atmPrf&amp;quot; global temperature data in the stratosphere

Das, Uma; Chen, Pan

doi:10.5194/amt-7-731-2014

Cited by 27 publications

(18 citation statements)

References 25 publications

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“…Higher concentrations or gradients of water vapor near the tropopause are not an error source this way. The "wetPrf" and dry temperature "atmPrf" profiles agree extremely well in a validation study by Das and Pan [2014], with absolute zero difference above the 200 hPa level. Less than 1% of the profiles is rejected by a preliminary quality control.…”

Section: Methodssupporting

confidence: 53%

Synoptic‐scale behavior of the extratropical tropopause inversion layer

Kedzierski

Matthes

Bumke

2015

Geophysical Research Letters

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High‐resolution GPS radio occultation temperature profiles from the COSMIC satellite mission (2007–2013) are used to obtain daily snapshots of the strength of the extratropical tropopause inversion layer (TIL). Its horizontal structure and day‐to‐day variability are linked to the synoptic situation at near‐tropopause level. The strength of the TIL in cyclonic as well as anticyclonic conditions is investigated by separating relative vorticity into curl and shear terms. The analysis shows that the TIL has high zonal variability, and its strength is instantaneously adjusted to the synoptic situation at near‐tropopause level. Our key finding is that the TIL within midlatitude ridges in winter is as strong as or stronger than the TIL in polar summer. The strongest TIL in anticyclonic conditions is related to the shear term, while the weaker TIL in cyclonic conditions is enhanced by the curl term.

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Section: Methodssupporting

confidence: 53%

Synoptic‐scale behavior of the extratropical tropopause inversion layer

Kedzierski

Matthes

Bumke

2015

Geophysical Research Letters

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“…In this paper, we use GPS wet profile (wetPrf) retrieved at 100 m vertical resolution using a one-dimensional variational technique based on ECMWF analysis. The wetPrf and GPS atmospheric profile (atmPrf, derived assuming no water vapor in the air) temperatures are essentially the same at 200-10 hPa, but at altitudes lower than the 200 hPa level the errors in atmPrf could be as high as ∼ 3 K due to neglect of water vapor (Das and Pan, 2014). Despite being retrieved at 100 m resolution, the actual vertical resolution ranges from 0.5 km in the lower troposphere to ∼ 1 km in the middle atmosphere (Kursinski et al, 1997).…”

Section: Gps Temperaturementioning

confidence: 96%

The impact of temperature vertical structure on trajectory modeling of stratospheric water vapor

et al. 2015

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Abstract. Lagrangian trajectories driven by reanalysis meteorological fields are frequently used to study water vapor (H 2 O) in the stratosphere, in which the tropical cold-point temperatures regulate the amount of H 2 O entering the stratosphere. Therefore, the accuracy of temperatures in the tropical tropopause layer (TTL) is of great importance for understanding stratospheric H 2 O abundances. Currently, most reanalyses, such as the NASA MERRA (Modern Era Retrospective -analysis for Research and Applications), only provide temperatures with ∼ 1.2 km vertical resolution in the TTL, which has been argued to miss finer vertical structure in the tropopause and therefore introduce uncertainties in our understanding of stratospheric H 2 O. In this paper, we quantify this uncertainty by comparing the Lagrangian trajectory prediction of H 2 O using MERRA temperatures on standard model levels (traj.MER-T) to those using GPS temperatures at finer vertical resolution (traj.GPS-T), and those using adjusted MERRA temperatures with finer vertical structures induced by waves (traj.MER-Twave). It turns out that by using temperatures with finer vertical structure in the tropopause, the trajectory model more realistically simulates the dehydration of air entering the stratosphere. But the effect on H 2 O abundances is relatively minor: compared with traj.MER-T, traj.GPS-T tends to dry air by ∼ 0.1 ppmv, while traj.MERTwave tends to dry air by 0.2-0.3 ppmv. Despite these differences in absolute values of predicted H 2 O and vertical dehydration patterns, there is virtually no difference in the interannual variability in different runs. Overall, we find that a tropopause temperature with finer vertical structure has limited impact on predicted stratospheric H 2 O.

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“…Compared to the global radiosonde data, a small bias of −0.09 K ± 1.72 K was observed in the height range from 925 to 10 hPa. On the other hand, Das and Pan (2014) reported that the temperature differences between CDAAC wetPrf (wet) and atmPrf (dry) version 2010.2640 are nearly zero from 200 to 10 hPa. Although the dry temperature retrieval deviates from the real temperature in a moist atmosphere (Scherllin-Pirscher et al 2011), the atmPrf version 2010.2640 is not affected by water vapor above about 10 km.…”

Section: Cosmic Gps-romentioning

confidence: 99%

Comparison of three retrievals of COSMIC GPS radio occultation results in the tropical upper troposphere and lower stratosphere

Noersomadi

Tsuda

2017

Earth Planets Space

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Combining geometrical optics (GO) and wave optics (WO), the COSMIC data analysis and archive center (CDAAC) retrieved two sets of dry atmosphere temperatures (T) from COSMIC GPS radio occultation (GPS-RO), which are called atmPrf2010 and atmPrf2013. In atmPrf2010, the sewing height between WO and GO varies between 10 and 20 km, but is fixed at 20 km for atmPrf2013. The height resolution of the atmPrf2010 depends on the sewing height, while the T profiles by atmPrf2013 are smoothed over 500 m. We also derived T by applying WO throughout the troposphere and the stratosphere up to a 30-km altitude, which is called rishfsi2013. The three retrievals have different characteristics in the height resolution around the tropopause. Therefore, we aim to examine a possible discrepancy in the statistical results of the cold-point tropopause (CPT) and the lapse rate tropopause (LRT) among the three datasets, conducting their inter-comparisons as well as the comparison between GPS-RO and the simultaneous radiosonde dataset. We investigate the T variations in the upper troposphere and lower stratosphere (UTLS) over the tropics from October 1, 2011, to March 31, 2012, when radiosonde soundings were conducted as the CINDY-DYNAMO 2011 campaign. The mean T profiles are consistent between atmPrf2010 and atmPrf2013, but rishfsi2013 results are colder (warmer) than the CDAAC retrievals below (above) the tropopause. The mean T difference between atmPrf2013 and atmPrf2010 is 0.17 K at the cold-point tropopause (CPT) and −0.38 K at the lapse rate tropopause (LRT). On the other hand, rishfsi2013 shows a colder T at CPT by −0.77 and −0.59 K relative to atmPrf2013 and atmPrf2010, respectively, and the warmer T by 0.60 and 0.20 Kd at LRT. During CINDY-DYNAMO, we found 134 radiosonde soundings that coincide with GPS-RO within ±3 h and are collocated within 200 km from GPS-RO. The mean T difference at CPT from the radiosondes is 0.32, 0.49 and −0.24 K for atmPrf2010, atmPrf2013 and rishfsi2013, respectively. Both atmPrf2013 and atmPrf2010 have a positive bias at CPT, while rishfsi2013 has a negative one. Similar comparisons at LRT are −0.45, −0.69 and −0.41 K, respectively, showing a negative bias for all GPS-RO retrievals. The results show that rishfsi2013 is consistent with the retrievals at CDAAC and the radiosondes. Due to its good height resolution, rishfsi2013 is useful for studies on mesoscale T perturbations in the UTLS.

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Validation of FORMOSAT-3/COSMIC level 2 "atmPrf" global temperature data in the stratosphere

Cited by 27 publications

References 25 publications

Synoptic‐scale behavior of the extratropical tropopause inversion layer

Synoptic‐scale behavior of the extratropical tropopause inversion layer

The impact of temperature vertical structure on trajectory modeling of stratospheric water vapor

Comparison of three retrievals of COSMIC GPS radio occultation results in the tropical upper troposphere and lower stratosphere

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