scholarly journals Precipitation and Latent Heating Characteristics of the Major Tropical Western Pacific Cloud Regimes

2008 ◽  
Vol 21 (17) ◽  
pp. 4348-4364 ◽  
Author(s):  
Christian Jakob ◽  
Courtney Schumacher
Keyword(s):  
Western Pacific ◽  
Convective Precipitation ◽  
Heating Regime ◽  
Latent Heating ◽  
Precipitation Regime ◽  
Tropical Western Pacific ◽  
Cloud Regime ◽  
Precipitation Regimes ◽  
Trmm Precipitation ◽  
Cloud Regimes

Abstract An objective tropical cloud regime classification based on daytime averaged cloud-top pressure and optical thickness information from the International Satellite Cloud Climatology Project (ISCCP) is combined with precipitation and latent heating characteristics derived using the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). TRMM precipitation information is stratified into the ISCCP regimes in the tropical western Pacific (TWP), revealing the following three major precipitation regimes: a heavy (12 mm day−1) precipitation regime dominated by stratiform precipitation and top-heavy latent heating; a regime with moderate (5 mm day−1) precipitation amounts, mostly convective in nature with more midlevel latent heating; and a low (2 mm day−1) precipitation regime with a relatively large rain contribution from shallow convection, compared to the other regimes. Although three of the ISCCP cloud regimes are linked to the more convective, moderate precipitation regime, only one of the cloud regimes is associated with the more stratiform, top-heavy latent heating regime, making the ISCCP regimes a potentially useful tool for the further study of this dynamically important tropical weather state. Similarly, only one cloud regime is associated with the more shallow convective precipitation regime. In terms of the TWP, precipitation and latent heating are dominated by the relatively infrequent (15%) occurrence of the strongly precipitating top-heavy latent heating state and by the frequent (>30%) occurrence of one of the more moderately precipitating convective states. The low precipitation/shallow cumulus regime occurs often (i.e., 25% of the time) but does not contribute strongly to the overall precipitation and latent heating. Each of these regimes also shows distinct geographical patterns in the TWP, thus providing insight into the distribution of convective and stratiform rain across the tropics. This study confirms the potential usefulness of the objective regime classification based on ISCCP, and it opens several new avenues for studying the interaction of convection with the large-scale tropical circulation.

Evaluation of GPROF V05 Precipitation Retrievals under Different Cloud Regimes

2021 ◽  
Keyword(s):  
Discrete Systems ◽  
The United States ◽  
Precipitation Variability ◽  
Substantial Fraction ◽  
Precipitation Regime ◽  
Surface Type ◽  
Precipitation Regimes ◽  
Channel Configuration ◽  
Global Precipitation ◽  
Cloud Regimes

AbstractPrecipitation retrievals from passive microwave satellite observations form the basis of many widely used precipitation products, but the performance of the retrievals depends on numerous factors such as surface type and precipitation variability. Previous evaluation efforts have identified bias dependence on precipitation regime, which may reflect the influence on retrievals of recurring factors. In this study, the concept of a regime-based evaluation of precipitation from the Goddard Profiling (GPROF) algorithm is extended to cloud regimes. Specifically, GPROF V05 precipitation retrievals under four different cloud regimes are evaluated against ground radars over the United States. GPROF is generally able to accurately retrieve the precipitation associated with both organized convection and less organized storms, which collectively produce a substantial fraction of global precipitation. However, precipitation from stratocumulus systems is underestimated over land and overestimated over water. Similarly, precipitation associated with trade cumulus environments is underestimated over land, while biases over water depend on the sensor’s channel configuration. By extending the evaluation to more sensors and suppressed environments, these results complement insights previously obtained from precipitation regimes, thus demonstrating the potential of cloud regimes in categorizing the global atmosphere into discrete systems.

scholarly journals The Radiative, Cloud, and Thermodynamic Properties of the Major Tropical Western Pacific Cloud Regimes

2005 ◽  
Vol 18 (8) ◽  
pp. 1203-1215 ◽  
Author(s):  
Christian Jakob ◽  
George Tselioudis ◽  
Timothy Hume
Keyword(s):  
Thermodynamic Properties ◽  
Thermodynamic Characteristics ◽  
The Other ◽  
Western Pacific ◽  
Cloud Properties ◽  
Tropical Western Pacific ◽  
Potential Applications ◽  
Shallow Clouds ◽  
Atmospheric Radiation Measurement ◽  
Cloud Regimes

Abstract This study investigates the radiative, cloud, and thermodynamic characteristics of the atmosphere separated into objectively defined cloud regimes in the tropical western Pacific (TWP). A cluster analysis is applied to 2 yr of daytime-only data from the International Satellite Cloud Climatology Project (ISCCP) to identify four major cloud regimes in the TWP region. A variety of data collected at the Department of Energy’s Atmospheric Radiation Measurement Program (ARM) site on Manus Island is then used to identify the main characteristics of the regimes. Those include surface and top-of-the-atmosphere radiative fluxes and cloud properties derived from a suite of ground-based active remote sensors, as well as the temperature and water vapor distribution measured from radiosondes. The major cloud regimes identified in the TWP area are two suppressed regimes—one dominated by the occurrence of mostly shallow clouds, the other by thin cirrus—as well as two convectively active regimes—one exhibiting a large coverage of optically thin cirrus clouds, the other characterized by a large coverage with optically thick clouds. All four of these TWP cloud regimes are shown to exist with varying frequency of occurrence at the ARM site at Manus. It is further shown that the detailed data available at that site can be used to characterize the radiative, cloud, and thermodynamic properties of each of the regimes, demonstrating the potential of the regime separation to facilitate the extrapolation of observations at one location to larger scales. A variety of other potential applications of the regime separation are discussed.

scholarly journals Convective response to large-scale forcing in the Tropical Western Pacific simulated by spCAM5 and CanAM4.3

2018 ◽  
Author(s):  
Toni Mitovski ◽  
Jason N. S. Cole ◽  
Norman A. McFarlane ◽  
Knut von Salzen ◽  
Guang J. Zhang
Keyword(s):  
Large Scale ◽  
Convective Available Potential Energy ◽  
Atmospheric Model ◽  
Western Pacific ◽  
Convective Precipitation ◽  
Near Surface ◽  
Tropical Western Pacific ◽  
Community Atmosphere Model ◽  
Hourly Output ◽  
Precipitation Events

Abstract. Changes in the large-scale environment during convective precipitation events in the Tropical Western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) is compared against those simulated by version 5.0 of the super parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT), and near surface vertical velocity (ω) over the time period May–July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation ( 2 mm h−1). In spCAM5 5 % of convective precipitation events lasted less than 1.5 h and 75 % lasted between 1.5 and 3.0 h while in CanAM4.3 80 % of the events lasted less than 1.5 h. Convective precipitation in spCAM5 is found to be a function of dCAPELSFT and the large-scale near surface ω with variations in ω slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.

scholarly journals Convective response to large-scale forcing in the tropical western Pacific simulated by spCAM5 and CanAM4.3

2019 ◽  
Vol 12 (5) ◽  
pp. 2107-2117 ◽  
Author(s):  
Toni Mitovski ◽  
Jason N. S. Cole ◽  
Norman A. McFarlane ◽  
Knut von Salzen ◽  
Guang J. Zhang
Keyword(s):  
Large Scale ◽  
Convective Available Potential Energy ◽  
Atmospheric Model ◽  
Western Pacific ◽  
Convective Precipitation ◽  
Near Surface ◽  
Tropical Western Pacific ◽  
Community Atmosphere Model ◽  
Hourly Output ◽  
Precipitation Events

Abstract. Changes in the large-scale environment during convective precipitation events in the tropical western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) are compared against those simulated by version 5.0 of the super-parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT) and near-surface vertical velocity (ω) over the time period May–July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation (<0.2 mm h−1) and underestimates the frequency of extreme convective precipitation (>2 mm h−1). In spCAM5, 5 % of convective precipitation events lasted less than 1.5 h and 75 % lasted between 1.5 and 3.0 h, while in CanAM4.3 80 % of the events lasted less than 1.5 h. Convective precipitation in spCAM5 is found to be a function of dCAPELSFT and the large-scale near-surface ω with variations in ω slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.

Role of Latent Heating over the Tropical Western Pacific in Surface Temperature Change over North America during Boreal Spring

2018 ◽  
Vol 31 (6) ◽  
pp. 2169-2184 ◽  
Author(s):  
Bian He ◽  
Song Yang
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Function Analysis ◽  
Western Pacific ◽  
Jet Stream ◽  
Latent Heating ◽  
Surface Temperature Change ◽  
Westerly Jet ◽  
Tropical Western Pacific ◽  
Baroclinic Model

Based on observational data, a linear baroclinic model, and an atmospheric general circulation model (AGCM), the major modes of spring precipitation over the tropical Asian and Pacific regions are identified. and the influence of latent heating over the tropical western Pacific (TWP) on global climate is investigated. Results show that the first mode of empirical orthogonal function analysis explains 20% of the total variance in March, the largest in spring, with the maximum center located over the TWP. The precipitation is highly positively correlated with local sea surface temperature (SST) in March, which suggests that the warming SST is the trigger for the precipitation over the TWP. Further analysis suggests that an increase in latent heating over the TWP, especially in March, can produce Rossby waves along the westerly jet, which causes an increase in surface temperature over North America. The propagation intensity decreases from March to May. The changes in location and strength of the westerly jet stream in the Northern Hemisphere are responsible for this decrease. Experiments with both a linear baroclinic model and an AGCM verify the above hypothesis. The study highlights that the spatial distributions of latent heating and westerly jet stream are the two key factors for the formation of teleconnection patterns from eastern Asia to North America.

scholarly journals The climatic imprint of bimodal distributions in vegetation cover for western Africa

2016 ◽  
Vol 13 (11) ◽  
pp. 3343-3357 ◽  
Author(s):  
Zun Yin ◽  
Stefan C. Dekker ◽  
Bart J. J. M. van den Hurk ◽  
Henk A. Dijkstra
Keyword(s):  
Land Cover ◽  
Congo Basin ◽  
Shortwave Radiation ◽  
Mean Annual Precipitation ◽  
Above Ground Biomass ◽  
Precipitation Regime ◽  
Ground Biomass ◽  
Western Africa ◽  
Precipitation Regimes ◽  
Woody Cover

Abstract. Observed bimodal distributions of woody cover in western Africa provide evidence that alternative ecosystem states may exist under the same precipitation regimes. In this study, we show that bimodality can also be observed in mean annual shortwave radiation and above-ground biomass, which might closely relate to woody cover due to vegetation–climate interactions. Thus we expect that use of radiation and above-ground biomass enables us to distinguish the two modes of woody cover. However, through conditional histogram analysis, we find that the bimodality of woody cover still can exist under conditions of low mean annual shortwave radiation and low above-ground biomass. It suggests that this specific condition might play a key role in critical transitions between the two modes, while under other conditions no bimodality was found. Based on a land cover map in which anthropogenic land use was removed, six climatic indicators that represent water, energy, climate seasonality and water–radiation coupling are analysed to investigate the coexistence of these indicators with specific land cover types. From this analysis we find that the mean annual precipitation is not sufficient to predict potential land cover change. Indicators of climate seasonality are strongly related to the observed land cover type. However, these indicators cannot predict a stable forest state under the observed climatic conditions, in contrast to observed forest states. A new indicator (the normalized difference of precipitation) successfully expresses the stability of the precipitation regime and can improve the prediction accuracy of forest states. Next we evaluate land cover predictions based on different combinations of climatic indicators. Regions with high potential of land cover transitions are revealed. The results suggest that the tropical forest in the Congo basin may be unstable and shows the possibility of decreasing significantly. An increase in the area covered by savanna and grass is possible, which coincides with the observed regreening of the Sahara.

scholarly journals LC–MS/MS Analysis of Ciguatoxins Revealing the Regional and Species Distinction of Fish in the Tropical Western Pacific

2021 ◽  
Vol 9 (3) ◽  
pp. 299 ◽  
Author(s):  
Naomasa Oshiro ◽  
Takumi Tomikawa ◽  
Kyoko Kuniyoshi ◽  
Akira Ishikawa ◽  
Hajime Toyofuku ◽  
...  
Keyword(s):  
Fish Species ◽  
The Philippines ◽  
Western Pacific ◽  
Tropical Region ◽  
Northern Coast ◽  
Coastal Regions ◽  
Main Island ◽  
Tropical Western Pacific ◽  
The Pacific ◽  
Fish Samples

Ciguatera fish poisoning (CFP) is one of the most frequently reported seafood poisoning diseases. It is endemic to the tropical region and occurs most commonly in the regions around the Pacific Ocean, Indian Ocean, and Caribbean Sea. The principal toxins causing CFP are ciguatoxins (CTXs). In the Pacific region, more than 20 analogs of CTXs have been identified to date. Based on their skeletal structures, they are classified into CTX1B-type and CTX3C-type toxins. We have previously reported species-specific and regional-specific toxin profiles. In this study, the levels and profiles of CTXs in fish present in the tropical western Pacific regions were analyzed using the liquid chromatography–tandem mass spectrometry (LC–MS/MS) technique. Forty-two fish specimens, belonging to the categories of snappers, groupers, Spanish mackerel, and moray eel, were purchased from various places such as Fiji, the Philippines, Thailand, and Taiwan. Only the fish captured from Fijian coastal waters contained detectable amounts of CTXs. The toxin levels in the fish species found along the coastal regions of the Viti Levu Island, the main island in Fiji, and the toxin profiles were significantly different from those of the fish species present in other coastal regions. The toxin levels and profiles varied among the different fish samples collected from different coastal areas. Based on the toxin levels and toxin profiles, the coast was demarcated into three zones. In Zone-1, which covers the northern coast of the main island and the regions of the Malake Island and Korovau, CTXs in fish were below the detection level. In Zone-2, CTX3C-type toxins were present in low levels in the fish. CTX1B-type and CTX3C-type toxins co-occurred in the fish present in Zone-3. The toxin profiles may have reflected the variation in Gambierdiscus spp.

scholarly journals An observationally constrained evaluation of the oxidative capacity in the tropical western Pacific troposphere

2016 ◽  
Vol 121 (12) ◽  
pp. 7461-7488 ◽  
Author(s):  
Julie M. Nicely ◽  
Daniel C. Anderson ◽  
Timothy P. Canty ◽  
Ross J. Salawitch ◽  
Glenn M. Wolfe ◽  
...  
Keyword(s):  
Oxidative Capacity ◽  
Western Pacific ◽  
Tropical Western Pacific
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