Cirrus cloud1/6/2023 ![]() (2017, hereinafter L17) describe multiyear ground-based NASA Micro-Pulse Lidar Network (MPLNET, 532 nm Welton et al. This study and hypothesis lay the basis for an extrapolation of these MPLNET experiments to satellite-based lidar cirrus cloud datasets.Ĭampbell et al. ![]() We hypothesize that subarctic interannual cloud variability is likely a considerable influence on global cirrus cloud forcing sensitivity, given the irregularity of polar versus midlatitude synoptic weather intrusions. Increasing tropopause heights, inducing higher and colder cirrus, have likely increased regional forcing over the last 40 years. Evidence in historical reanalysis data suggests that daytime cirrus forcing in and around the subarctic likely once was exclusively negative. ![]() This study does not completely confirm Campbell et al., as values are not found as exclusively negative. m −2 over land in Maryland), and turns negative moving poleward.m −2 over ocean at Singapore), becomes neutral in the midlatitudes (0.03–0.27 W.hypothesize a global meridional daytime TOA CRF gradient that begins as positive at the equator (2.20–2.59 W This subarctic study completes a now trilogy of MPLNET ground-based cloud forcing investigations, following midlatitude and tropical studies by Campbell et al. Two-year-averaged daytime TOA CRF is estimated to be between −1.08 and 0.78 W Sample-relative net average TOA CRF distributions vs log 10(COD) for the (a) annual 2017 (solid lines) and 2018 (dashed lines) daytime samples as a function of their 20- (blue) and 30-sr (red) estimates and for the 20 (b) summer and (c) winter periods.Ĭirrus cloud daytime top-of-the-atmosphere radiative forcing (TOA CRF) is estimated for a 2-yr NASA Micro-Pulse Lidar Network (532 nm MPLNET) dataset collected at Fairbanks, Alaska. m −2), and (g)–(i) absolute normalized net TOA CRF solved at Fairbanks.Interannual values are solved after daily data point smoothing is done with a low-bandpass filter.įor (left) the bulk 2-yr sample and for individual years (center) 2017 and (right) 2018, (a)–(c) the MPLNET-derived daytime cirrus cloud sample-relative frequency, (d)–(f) sample-relative average net TOA CRF (W Thirty-nine-year (1980–2018) seasonal 2.0-PVU (summer and winter) height anomalies and trend analyses solved over the Arctic domain (70°–90°N) from ERA5 datasets. Sample-relative daytime cirrus cloud occurrence histograms derived from continuous NASA MPLNET observations at Fairbanks during (top) 2017 and (bottom) 2018 as a function of COD (30-sr solutions only see insets for bulk percentages) vs CTT (a),(d) annually (b),(e) from May to October and (c),(f) from November to March. (2015), from June 2006 to May 2017 centered near Fairbanks (white star) (a) annually, (b) from May to October, and (c) from November to March. It’s also possible for cirrus fibratus clouds to be formed from sheared aircraft contrails high up in the atmosphere (cirrus fibratus homomutatus).Cirrus cloud absolute occurrence rate frequencies at 2.5° × 2.5° resolution estimated from NASA CALIOP level 2 cloud-layer products, and thus subcategorized on the basis of definitions outlined in Campbell et al. Many times, cirrus fibratus and cirrus uncinus can be seen in the same sky. The cloud varieties cirrus vertebratus and cirrus intortus are more often than not found accompanied with a fibratus classification as well.Īs a cloudspotter, know that cirrus uncinus cloud formations are very similar to fibratus clouds, the difference being uncinus clouds have a distinct hook and comma shape in addition to being wispy like the fibratus species. It’s not unusual to see the fibratus cloud species paired up with other cirrus cloud varieties, such as duplicatus (multilayered) and radiatus (parallel bands and strips). Take that with a grain of salt: they can also be an indication of fair weather as well. The fibratus species can bring out a halo phenomena in both clouds, as they’re composed of ice crystals.įibratus clouds might be an indication of a warm front on the horizon, which might mean bad weather. While cirrostratus generally aren’t accompanied with a lot of detail, they’re sometimes given detail through the fibratus cloud species. You’re probably more likely to see a fibratus cloud in a cirrus cloud versus a cirrostratus cloud. The species is a fairly common occurrence in cirrus clouds. They’re a favorite amongst cloudspotters as they have an ethereal appearance, especially when viewed at sunset. Translated from latin meaning fibered, their cloud abbreviations can be respectively written as ‘Ci fib’ and ‘Cs fib’. The ‘fibratus’ cloud species is found in only high-altitude cirrus and cirrostratus cloud types, and is one of only two species that’s associated with cirrostratus clouds. ![]()
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