Stratiform Cloud—Inversion Characterization During the Arctic Melt Season

Sedlar, Joseph; Tjernström, Michael

doi:10.1007/s10546-009-9407-1

Cited by 75 publications

(93 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Seasonal variation in temperature inversion occurrence is very similar to its humidity inversion counterparts, and the temperature inversion frequency of occurrence above an AMC is about 8 times as high as that below an AMC (Figures 7a and 7b). This result agrees well with previous studies, where specific humidity inversions occurred coincidently with temperature inversions over the Arctic [Sedlar and Tjernström, 2009]. The strong inversion occurrences for both humidity and temperature above an AMC provide the moisture sources from above for the formation and maintenance of AMCs.…”

Section: 1002/2014jd023022supporting

confidence: 93%

Characterizing Arctic mixed‐phase cloud structure and its relationship with humidity and temperature inversion using ARM NSA observations

Qiu

Dong

et al. 2015

JGR Atmospheres

View full text Add to dashboard Cite

In this study, the characteristics of the Arctic mixed-phase cloud (AMC) have been investigated using data collected at the Atmospheric Radiation Measurement North Slope Alaska site from October 2006 to September 2009. AMC has an annual occurrence frequency of 42.3%, which includes 18.7% of single-layered AMCs and 23.6% for multiple layers. Two cloud base heights (CBHs) are defined from ceilometer and micropulse lidar (MPL) measurements. For single-layered AMC, the ceilometer-derived CBH represents the base of the liquid-dominant layer near the cloud top, while MPL-derived CBH represents base of the lower ice-dominant layer. The annual mean CBHs from ceilometer and MPL measurements are 1.0 km and 0.6 km, respectively, with the largest difference (~1.0 km) occurring from December to March and the smallest difference in September. The humidity inversion occurrence decreases with increasing humidity inversion intensity (stronger in summer than in winter). During the winter months, AMC occurrences increase from 15% to 35% when the inversion intensity increases from 0.1 to 0.9 g/kg. On the contrary, despite a higher frequency of strong humidity inversion in summer, AMC occurrences are nearly invariant for different inversion intensities. On average, humidity and temperature inversion frequencies of occurrence above an AMC are 5 and 8 times, respectively, as high as those below an AMC. The strong inversion occurrences for both humidity and temperature above an AMC provide the moisture sources from above for the formation and maintenance of AMCs. This result helps to reconcile the persistency of AMCs even when the Arctic surface is covered by snow and ice.

show abstract

Section: 1002/2014jd023022supporting

confidence: 93%

Characterizing Arctic mixed‐phase cloud structure and its relationship with humidity and temperature inversion using ARM NSA observations

Qiu

Dong

et al. 2015

JGR Atmospheres

View full text Add to dashboard Cite

show abstract

“…Sedlar and Tjernström (2009), Solomon et al (2011) and Sedlar et al (2012) found, however, that inversions of temperature and humidity typically coincide near the cloud top. A potential explanation for the different results is that the abovementioned studies mostly addressed the ice-covered Arctic Ocean, whereas the IGRA data set is more representative of the pan-Arctic land areas.…”

Section: Discussionmentioning

confidence: 98%

Characteristics of Arctic low-tropospheric humidity inversions based on radio soundings

2014

View full text Add to dashboard Cite

Abstract. Humidity inversions have a high potential importance in the Arctic climate system, especially for cloud formation and maintenance, in wide spatial and temporal scales. Here we investigate the climatology and characteristics of humidity inversions in the Arctic, including their spatial and temporal variability, sensitivity to the methodology applied and differences from the Antarctic humidity inversions. The study is based on data of the Integrated Global Radiosonde Archive (IGRA) from 36 Arctic stations between the years 2000 and 2009. The results indicate that humidity inversions are present on multiple levels nearly all the time in the Arctic atmosphere. Almost half (48 %) of the humidity inversions were found at least partly within the same vertical layer with temperature inversions, whereas the existence of the other half may, at least partly, be linked to uneven vertical distribution of horizontal moisture transport. A high atmospheric surface pressure was found to increase the humidity inversion occurrence, whereas relationships between humidity inversion properties and cloud cover were generally relatively weak, although for some inversion properties they were systematic. For example, humidity inversions occurred slightly more often and were deeper under clear sky than in overcast conditions for almost all stations. The statistics of Arctic humidity inversion properties, especially inversion strength, depth and base height, proved to be very sensitive to the instruments and methodology applied. For example, the median strength of the strongest inversion in a profile was twice as large as the median of all Arctic inversions. The most striking difference between the Arctic and Antarctic humidity inversions was the much larger range of the seasonal cycle of inversion properties in the Arctic. Our results offer a baseline for validation of weather prediction and climate models and also encourage further studies on humidity inversions due to the vital, but so far poorly understood, role of humidity inversions in Arctic cloud processes.

show abstract

“…Entrainment also becomes a source of boundary-layer moisture. Cloud tops penetrating into the lower inversion have been found to be a dominating feature in many Arctic observations, for example from cloud radar and temperature profiles from AOE-2001, ASCOS, SHEBA and at Barrow, Alaska, (Sedlar and Tjernström, 2009;Sedlar et al, 2012) and have been suggested as important for the persistence of Arctic mixed-phase stratocumulus clouds (Solomon et al, 2011).…”

Section: Vertical Structurementioning

confidence: 99%

Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS)

et al. 2012

View full text Add to dashboard Cite

Abstract. Understanding the rapidly changing climate in the Arctic is limited by a lack of understanding of underlying strong feedback mechanisms that are specific to the Arctic. Progress in this field can only be obtained by process-level observations; this is the motivation for intensive ice-breakerbased campaigns such as the Arctic Summer Cloud-Ocean Study (ASCOS), described here. However, detailed field observations also have to be put in the context of the largerscale meteorology, and short field campaigns have to be analysed within the context of the underlying climate state and temporal anomalies from this.To aid in the analysis of other parameters or processes observed during this campaign, this paper provides an overview of the synoptic-scale meteorology and its climatic anomaly during the ASCOS field deployment. It also provides a statistical analysis of key features during the campaign, such as key meteorological variables, the vertical structure of the lower troposphere and clouds, and energy fluxes at the surface. In order to assess the representativity of the ASCOS results, we also compare these features to similar observations obtained during three earlier summer experiments in the Arctic Ocean: the AOE-96, SHEBA and AOE-2001 expeditions.We find that these expeditions share many key features of the summertime lower troposphere. Taking ASCOS and the previous expeditions together, a common picture emerges with a large amount of low-level cloud in a well-mixed shallow boundary layer, capped by a weak to moderately strong inversion where moisture, and sometimes also cloud top, penetrate into the lower parts of the inversion. Much of the boundary-layer mixing is due to cloud-top cooling and subsequent buoyant overturning of the cloud. The cloud layer may, or may not, be connected with surface processes depending on the depths of the cloud and surface-based boundary layers and on the relative strengths of surface-shear and cloud-generated turbulence. The latter also implies a connection between the cloud layer and the free troposphere through entrainment at cloud top.

show abstract

Stratiform Cloud—Inversion Characterization During the Arctic Melt Season

Cited by 75 publications

References 39 publications

Characterizing Arctic mixed‐phase cloud structure and its relationship with humidity and temperature inversion using ARM NSA observations

Characterizing Arctic mixed‐phase cloud structure and its relationship with humidity and temperature inversion using ARM NSA observations

Characteristics of Arctic low-tropospheric humidity inversions based on radio soundings

Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS)

Contact Info

Product

Resources

About