On the Use of Probability of Clear Line of Sight Models in Parameterizing Surface Downwelling Longwave Radiation in the Tropical Western Pacific

Abstract The plane-parallel horizontal (PPH) hypothesis used to approximate clouds in GCMs neglects three-dimensional cloud effects. Such effects can amount to as much as 20 W m−2 in longwave radiation. Several investigators have proposed accounting for longwave three-dimensional cloud effects by using information on the probability of clear line of sight (PCLoS) to modify the PPH approximation. This study investigates the PCLoS at the Atmosphere Radiation Measurement (ARM) Program’s Tropical Western Pacific (TWP) site. PCLoS is estimated for single-layer tropical marine cumulus cases for 2-h intervals using the Whole Sky Imager (WSI) observations at the Manus and Nauru sites. PCLoS estimates are compared to calculations from a set of simple PCLoS models using measured cloud field statistics as input. A summary of the PCLoS at the TWP site is presented in addition to a statistical summary of retrieved cloud field characteristics. The results are used to investigate the spatial variability of the PCLoS and to test the usefulness of the parameterization of effective cloud fraction.

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Recent Climate Change in the Tropical Western Pacific and Indian Ocean Regions as Detected by Outgoing Longwave Radiation Records

Journal of Climate ◽

10.1175/1520-0442(1997)010<0636:rccitt>2.0.co;2 ◽

1997 ◽

Vol 10 (4) ◽

pp. 636-646 ◽

Cited By ~ 32

Author(s):

Pao-Shin Chu ◽

Jian-Bo Wang

Keyword(s):

Climate Change ◽

Indian Ocean ◽

Outgoing Longwave Radiation ◽

Longwave Radiation ◽

Western Pacific ◽

Tropical Western Pacific ◽

Recent Climate Change ◽

Recent Climate

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ENSO surface longwave radiation forcing over the tropical Pacific

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-2013-2007 ◽

2007 ◽

Vol 7 (8) ◽

pp. 2013-2026 ◽

Cited By ~ 8

Author(s):

K. G. Pavlakis ◽

D. Hatzidimitriou ◽

E. Drakakis ◽

C. Matsoukas ◽

A. Fotiadi ◽

...

Keyword(s):

Time Series ◽

El Niño ◽

El Nino ◽

Longwave Radiation ◽

Western Pacific ◽

Radiative Cooling ◽

Central Pacific ◽

The Mean ◽

Downwelling Longwave Radiation ◽

The Western Pacific

Abstract. We have studied the spatial and temporal variation of the surface longwave radiation (downwelling and net) over a 21-year period in the tropical and subtropical Pacific Ocean (40 S–40 N, 90 E–75 W). The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database and reanalysis data from NCEP/NCAR (acronyms explained in main text), for the key atmospheric and surface input parameters. An excellent correlation was found between the downwelling longwave radiation (DLR) anomaly and the Niño-3.4 index time-series, over the Niño-3.4 region located in the central Pacific. A high anti-correlation was also found over the western Pacific (15–0 S, 105–130 E). There is convincing evidence that the time series of the mean downwelling longwave radiation anomaly in the western Pacific precedes that in the Niño-3.4 region by 3–4 months. Thus, the downwelling longwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to asses whether or not El Niño or La Niña conditions prevail. Over the Niño-3.4 region, the mean DLR anomaly values range from +20 Wm−2 during El Niño episodes to −20 Wm−2 during La Niña events, while over the western Pacific (15–0 S, 105–130 E) these values range from −15 Wm−2 to +10 Wm−2, respectively. The long- term average (1984–2004) distribution of the net downwelling longwave radiation at the surface over the tropical and subtropical Pacific for the three month period November-December-January shows a net thermal cooling of the ocean surface. When El Niño conditions prevail, the thermal radiative cooling in the central and south-eastern tropical Pacific becomes weaker by 10 Wm−2 south of the equator in the central Pacific (7–0 S, 160–120 W) for the three-month period of NDJ, because the DLR increase is larger than the increase in surface thermal emission. In contrast, the thermal radiative cooling over Indonesia is enhanced by 10 Wm−2 during the early (August–September–October) El Niño phase.

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ENSO surface longwave radiation forcing over the tropical Pacific

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-12895-2006 ◽

2006 ◽

Vol 6 (6) ◽

pp. 12895-12928 ◽

Cited By ~ 1

Author(s):

K. G. Pavlakis ◽

D. Hatzidimitriou ◽

E. Drakakis ◽

C. Matsoukas ◽

A. Fotiadi ◽

...

Keyword(s):

Time Series ◽

El Niño ◽

El Nino ◽

Longwave Radiation ◽

Western Pacific ◽

Radiative Cooling ◽

Central Pacific ◽

The Mean ◽

Downwelling Longwave Radiation ◽

The Western Pacific

Abstract. We have studied the spatial and temporal variation of the surface longwave radiation (downwelling and net) over a 21-year period in the tropical and subtropical Pacific Ocean (40 S–40 N, 90 E–75 W). The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database and reanalysis data from NCEP/NCAR (acronyms explained in main text), for the key atmospheric and surface input parameters. An excellent correlation was found between the downwelling longwave radiation (DLR) anomaly and the Niño-3.4 index time-series, over the Niño-3.4 region located in the central Pacific. A high anti-correlation was also found over the western Pacific (15–0 S, 105–130 E). There is convincing evidence that the time series of the mean downwelling longwave radiation anomaly in the western Pacific precedes that in the Niño-3.4 region by 3–4 months. Thus, the downwelling longwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to asses whether or not El Niño or La Niña conditions prevail. Over the Niño-3.4 region, the mean DLR anomaly values range from +20 Wm−2 during El Niño episodes to –20 Wm−2 during La Niña events, while over the western Pacific (15–0 S, 105–130 E) these values range from –15 Wm−2 to +10 Wm−2, respectively. The long- term average (1984–2004) distribution of the net surface longwave radiation to the surface over the tropical and subtropical Pacific for the three month period November-December-January shows a net thermal cooling of the ocean surface. When El Niño conditions prevail, the thermal radiative cooling in the central and south-eastern tropical Pacific becomes weaker by 10 Wm−2 south of the equator in the central Pacific (7–0 S, 160–120 W) for the three-month period of NDJ, because the DLR increase is larger than the increase in surface thermal emission. In contrast, the thermal radiative cooling over Indonesia is enhanced by 10 Wm−2 during the early (August–September–October) El Niño phase.

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

Journal of Marine Science and Engineering ◽

10.3390/jmse9030299 ◽

2021 ◽

Vol 9 (3) ◽

pp. 299 ◽

Cited By ~ 2

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.

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