Cold Core Research Articles

Methodology development for calibration assessment using quasi-deep convective clouds with application to Aqua MODIS TEB.

Deep convective clouds (DCC) are identified by using a combination of brightness temperature (BT) and visible reflectance thresholds. Moreover, it is common practice to use daytime DCC measurements for the calibration assessment of reflective solar and longwave infrared (LWIR) bands. The DCC cold core is suitable for the MODIS Thermal Emissive Bands (TEB) calibration assessment; more specifically, for the offset effect in the quadratic calibration function. However, the reflected solar radiance in the daytime DCC measurements affects the midwave infrared (MWIR) bands. Thus, an assessment over low BT measurements is not applicable to these bands. Because of this, a quasi-DCC (qDCC) technique is developed for the MWIR bands calibration assessment. The feasibility of using nighttime DCC measurements is demonstrated by comparing the DCC and daytime qDCC techniques. A DCC normalization method is also developed to remove the DCC fluctuation impact and enhance the assessment accuracy. The DCC measurements' distribution is asymmetrical for all TEB, and their BT ranges fluctuate around 20 K. An empirical model is developed and applied to normalize the measurements over DCC to a reference temperature. After the normalization, the DCC and qDCC measurements' distributions are close to symmetrical and Gaussian in shape. These improvements are applied to the Aqua MODIS instrument. The calibration stability, noise performance, and consistency are evaluated for all Aqua MODIS TEB. Lastly, the Aqua MODIS formatter reset effect on the calibration offset bias between two mirror sides is analyzed, and a calibration coefficient correction is proposed for future calibration improvements.

Low-temperature chemistry induced by cosmic rays: positive and negative ion desorption from nitrile-bearing astrophysical ice analogues

ABSTRACT In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on the surface of ice-covered grains promoting the ejection of the processed material to the gas phase. We report the positive and negative secondary ion emission from pure CH3CN, C2H3CN, and i-C3H7CN ices due to the bombardment of heavy ions (252Cf fission fragments), simulating the incidence of cosmic rays on to icy surfaces. The secondary ions emitted from each sample were analysed by time-of-flight mass spectrometry, using Plasma Desorption Mass Spectrometry technique. Several ionic species were identified, indicating strong fragmentation on the frozen surface. Proton-transfer processes are suggested to play a role for positive ion desorption, as evidenced by the protonated RCNH+ parent molecules and (RCN)nH+ ionic clusters. The high electron affinity of the cyano radical seems to contribute to the strong emission of CN−, as well as anions attributed to the CHmCN− fragment and (RCN)nCN− cluster series. Sputtering and desorption of ion clusters (positive and negative) induced by heavy ion bombardment are suggested to constitute a route by which new neutral or ionized molecular species may be delivered to the gas phase where thermal desorption is negligible.

A new data structure for accelerating kinetic Monte Carlo method

The kinetic Monte Carlo simulation is a rigorous numerical approach to study the chemistry on dust grains in cold dense interstellar clouds. By tracking every single reaction in chemical networks step by step, this approach produces more precise results than other approaches but takes too much computing time. Here we present a method of a new data structure, which is applicable to any physical conditions and chemical networks, to save computing time for the Monte Carlo algorithm. Using the improved structure, the calculating time is reduced by 80 percent compared with the linear structure when applied to the osu-2008 chemical network at 10 K. We investigate the effect of the encounter desorption in cold cores using the kinetic Monte Carlo model with an accelerating data structure. We found that the encounter desorption remarkably decreases the abundance of grain-surface H2 but slightly influences the abundances of other species on the grain.

Dynamic and thermodynamic upper-ocean response to the passage of Bay of Bengal cyclones 'Phailin' and 'Hudhud': a study using a coupled modelling system.

Understanding the upper-ocean response to tropical cyclones (TCs) in terms of sea surface temperature (SST) cooling is of prime importance in the prediction of TC intensity. However, the magnitude of cooling during the passage of TC varies depending on storm characteristics and pre-existing upper-ocean conditions such as the presence of ocean eddy and upper-ocean stratification. The present study investigates the upper-ocean response to two post-monsoon Bay of Bengal (BoB) cyclones, Phailin (October 2013) and Hudhud (October 2014), those followed almost a similar track, in association with pre-existing oceanic conditions using a fully coupled ocean-atmosphere modelling system. The spatial structure and temporal evolution of SST cooling induced by the two cyclones and the physical processes governing the cooling are examined. Analysis shows that the intensity of Phailin is significantly reduced when it encountered the regime of lower tropical cyclone heat potential (TCHP) associated with pre-existing cold core eddy (CCE). Intense upwelling with an average of 0.6 m/h is observed over CCE that resulted in strong temperature tendency of - 4.2 °C prior to landfall. Though average TCHP in the generation region of Hudhud was 50 kJ/cm2, the storm drew sufficient energy from the underlying ocean due to its slow translation speed. Presence of shallow thermocline over extended region and weaker upper-ocean stratification enhanced SST cooling over a larger region after passage of the TC Hudhud. Finally, the present study brings in clarity that the upper-ocean condition and the relative position of the mesoscale oceanic features to the storm track are responsible for the intensification of the TC and the recovery of the ocean surface.

Dark matter and bubble nucleation in old neutron stars

We study the probability for nucleation of quark matter droplets in the dense cold cores of old neutron stars induced by the presence of a self-annihilating dark matter component, $\chi$. Using a parameterized form of the equation of state for hadronic and quark phases of ordinary matter, we explore the thermodynamic conditions under which droplet formation is facilitated by the energy injection from $\chi$ self-annihilations. We obtain the droplet nucleation time as a function of the dark matter candidate mass, $m_\chi$. We discuss further observational consequences.

Subduction‐Induced Upwelling of a Hydrous Transition Zone: Implications for the Cenozoic Magmatism in Northeast China

AbstractThe widespread Cenozoic basalts in northeast China are commonly thought to be related to the stagnation of the Pacific slab in the transition zone and its deep dehydration. By incorporating experimentally constrained phase diagrams of hydrous mantle and melting conditions at high pressures into two‐dimensional petrological‐thermomechanical models, here we model the interaction of a subducting slab with a hydrous transition zone (TZ) and examine its potential role in generating intracontinental magmatism. The model results show that descending of the oceanic slab first forces up the material in the TZ. Depending on the water content in the TZ, the upwelling hydrous material may undergo dehydration melting above the TZ. As a large slab stagnates within the TZ owing to the lower mantle resistance, the deep melting migrates progressively toward the overriding continent's interior, generating plutonic/volcanic rocks in the continental crust far away from the trench. The amount of deep melting and surface magmatism is obviously related to the amount of water stored in the TZ. In contrast, the water stored in the cold core of the subducting slab and released in the transition zone does not generate melting as it is entirely absorbed by mantle transition zone nominally anhydrous minerals. Comparing the model results with the distribution of the late Cenozoic basalts in northeast China, we suggest that the intracontinental magmatism there was likely caused by deep dehydration melting induced by the slab‐transition zone interaction.

Hemiaminal route for the formation of interstellar glycine: a computational study.

Calculations related to two simple two-step paths (path-I: [Formula: see text] path-II: [Formula: see text]) for the formation of glycine have been discussed. Calculations show that at interstellar conditions these two paths are feasible only in hot cores, not in the cold interstellar clouds (cold core formation is possible only if CH2 = NH, H2O (excess) and CO of path-II, react in a concerted manner). For the laboratory synthesis of glycine, the possibility suggested is via path-I and the reaction being carried out as controlled temperature one-pot synthesis. This study can also be extended to other α-amino acids and possibly enantiomeric excess can be expected. We think this work will not only be able to enrich our future understanding about the formation of amino acids in interstellar medium but also be able to suggest alternative paths for laboratory synthesis of amino acids using either Strecker's or Miller's ingredients. Graphical abstract Using computational calculations, two different reaction paths which go through a hemiaminal (α-hydroxyamine) intermediate have been proposed. It has been proposed that the reaction [Formula: see text] is a thermodynamically favorable reaction path in the laboratory conditions, if carried out as a controlled temperature one-pot synthesis. On the hand, it has been argued that the reaction[Formula: see text] is a feasible reaction path in the interstellar conditions, if it proceeds not via the hemiaminal route, rather in a concerted reaction path.

Sulphur-bearing and complex organic molecules in an infrared cold core

ABSTRACT Since the start of ALMA (Atacama Large Millimeter Array) observatory operation, new and important chemistry of infrared cold core was revealed. Molecular transitions at millimetre range are being used to identify and to characterize these sources. We have investigated the 231 GHz ALMA archive observations of the infrared dark cloud region C9, focusing on the brighter source that we called as IRDC-C9 Main. We report the existence of two substructures on the continuum map of this source: a compact bright spot with high chemistry diversity that we labelled as core, and a weaker and extended one, that we labelled as tail. In the core, we have identified lines of the molecules OCS(19−18), 13CS(5−4), and CH3CH2CN, several lines of CH3CHO and the k-ladder emission of 13CH3CN. We report two different temperature regions, while the rotation diagram of CH3CHO indicates a temperature of 25 K, the rotation diagram of 13CH3CN indicates a warmer phase at temperature of ∼450 K. In the tail, only the OCS(19−18) and 13CS(5−4) lines were detected. We used the nautilus and the radex codes to estimate the column densities and the abundances. The existence of hot gas in the core of IRDC-C9 Main suggests the presence of a protostar, which is not present in the tail.

BERING SEA: 2018 AS THE EXTREME LOW-ICE AND WARM YEA

Phenomenon of anomalous oceanographic conditions in the Bering Sea in 2018 is considered, with heightened air and water temperature and very low ice cover, as well as its consequences for the water structure, circulation, and chemical properties. These extreme conditions were formed on the background of warming tendency observed in the Bering Sea since 2014, but they were exceptional even relative to this background: deflections of some parameters from their normal values exceeded the standard deviations more than twice (> 2s). The main reason for such conditions was the southern winds prevalence over the entire Sea in winter, in opposite to usual regime when the southern winds blew over its southeastern part only; another factor was strengthened advection of the oceanic waters, still abnormally warm after the period of extreme warming in the North-East Pacific in 2014–2016. As the result, the ice cover in winter and spring was more than twice lower the normal values, the air and water temperatures through the year were above their normal values in 15 and 5 degrees Celsius, respectively. The winter convection was weakened that caused deepening of the cold subsurface layer core and prevented forming of the cold near-bottom water masses on the shelf that was usual for the Bering Sea. Under this considerable redistribution of the water density coupled with unusual wind regime, the water circulation changed, in particular in the northern Bering Sea where the Navarin Current were weakened or even absent and the northward water transport was realized through the eastern shelf delivering to the northern shelf and Bering Strait the coastal waters from Alaska instead of the deep-water basins waters, as usually. Strong advection of the oceanic waters through the Aleutian Straits promoted growth of nutrients concentrations and lowering of oxygen content in the intermediate layer of the Bering Sea. These extreme oceanographic conditions in the Bering Sea in 2018 were statistical outliers, atypical even for recent period of warming, but such conditions would be expected frequently if the warming will continue. Thus, phenomenon of the year 2018 could be useful for understanding and prediction of the oceanographic regime reconstruction in the nearest future.

X-ray spectroscopy evidence for plasma shell formation in experiments modeling accretion columns in young stars

Recent achievements in laboratory astrophysics experiments with high-power lasers have allowed progress in our understanding of the early stages of star formation. In particular, we have recently demonstrated the possibility of simulating in the laboratory the process of the accretion of matter on young stars [G. Revet et al., Sci. Adv. 3, e1700982 (2017)]. The present paper focuses on x-ray spectroscopy methods that allow us to investigate the complex plasma hydrodynamics involved in such experiments. We demonstrate that we can infer the formation of a plasma shell, surrounding the accretion column at the location of impact with the stellar surface, and thus resolve the present discrepancies between mass accretion rates derived from x-ray and optical-radiation astronomical observations originating from the same object. In our experiments, the accretion column is modeled by having a collimated narrow (1 mm diameter) plasma stream first propagate along the lines of a large-scale external magnetic field and then impact onto an obstacle, mimicking the high-density region of the stellar chromosphere. A combined approach using steady-state and quasi-stationary models was successfully applied to measure the parameters of the plasma all along its propagation, at the impact site, and in the structure surrounding the impact region. The formation of a hot plasma shell, surrounding the denser and colder core, formed by the incoming stream of matter is observed near the obstacle using x-ray spatially resolved spectroscopy.

Surface and Sub‐surface Ocean Response to Tropical Cyclone Phailin: Role of Pre‐existing Oceanic Features

AbstractThe upper oceanic thermal response induced by Tropical Cyclone Phailin (9–14 October 2013) under the influence of East India Coastal Current (EICC) and a cyclonic eddy is investigated and contrasted with the response from open ocean region using a high‐resolution HYbrid Coordinate Ocean Model simulation. There is significant cooling (7° C) inside the cold core eddy and negligible cooling (0.5° C) within the EICC region characterized by the shallow and deeper thermocline, respectively. Our analysis of mixed layer heat budget terms showed that the horizontal advection plays a significant role in determining the temperature tendency for the location within the EICC, in contrary to the general dominance of vertical processes as reported in previous studies during the cyclone period. The analysis for the locations inside eddy and open ocean concurs with the previous studies showing the dominance of vertical processes toward the temperature tendency. Further, near the coast, the surface cooling is minimal compared to the subsurface cooling, dominantly seen between 50‐ and 100‐m depth. This disparity indicates that the factors responsible for the surface temperature anomalies are different from those of subsurface. Our analysis of thermal signatures after the passage of cyclone showed that the EICC and cyclonic eddy contribute to the faster advection of cold wake and recovery of sea surface temperature to the prestorm state.

The Evolution and Role of Midtropospheric Cyclonic Vortex in the Formation of Super Typhoon Nepartak (2016)

AbstractBased on a successful cloud‐resolving simulation with the Weather Research and Forecasting Model, this study examines the evolution and the role of midtropospheric mesoscale cyclonic vortex in the formation of Super Typhoon Nepartak (2016). The midtropospheric vortex is correlated with the convective activity in pre‐Nepartak. Once the deep convection outbreaks, the midtropospheric vortex intensifies first via the vertical advection associated with the severe updrafts and then through the midlevel convergence associated with stratiform precipitation. As the stratiform precipitation dissipates, the midlevel vortex weakens slightly in the following shallow convection phase. The above‐described processes recur sequentially during the pregenesis of Nepartak, and the midtropospheric vortex demonstrates diurnal variations. Its intensification usually corresponds to the weakening of low‐level cyclonic circulation except for the deep convection phase, indicating that the development of midtropospheric vortex can inhibit the development of self‐sustained low‐level cyclonic circulation. Although the midtropospheric vortex is not always a quasi‐balanced perturbation, a cold core can be found in the lower troposphere below it during the most of the pregenesis stage. The appearance of the cold core enhances the low‐level temperature gradient around it, which favors convection burst. In addition, the closed cyclonic circulation associated with the midlevel vortex can serve as a pouch protecting the vorticity, moisture, and convection inside from the vertical wind shear and dry air intrusion when the low‐level and midlevel vortices are overlapped in the late pregenesis stage, which facilitates the sustained deep convection and the formation of Nepartak.

ТРАНСФОРМАЦИЯ И ЭФФЕКТЫ ВНУТРЕННИХ ВОЛН В ПРИБРЕЖНОЙ ЗОНЕ МОРЯ

Analysis of results of field experiments in the near-shore region of the Peter the Great Bay (the Sea pf Japan) is made from the point of view of internal waves (IW) influence on biological and geomorphologic processes in the shelf zone of sea. The main measured parameters were fluctuations of temperature, pressure and current velocity in the near-bottom layer in the near-shore region with bottom depth of 20–30 m. Fluctuations of temperature were measured with the help of anchored strings of 20–30 thermistors with 0.5 m interval, fluctuations of current velocity were measured at 10–15 levels with 1–3 m intervals. The typical for shoreward propagated IW was their nonlinear transformation with formation of stable discreet boluses - water volumes with cold cores, separated from surrounding medium by high-gradient layers. Propagating into shallow regions, IW stimulate mixing, bottom sediments resuspension and near-shore region ventilation. The boluses can propagate farther into shallow regions where continuous picnocline is absent, supplementing effects of IW and amplifying them. It is shown that biological effects of IW and boluses are caused by their considerable impact on the main parameters defining primary production of phytoplankton: biogens concentration, illumination, and fluctuations of temperature.

Characteristics of the Kamchatka Current Eddies

The characteristics of eddies in the Kamchatka Current from its source in the Bering Sea to Paramushir Island south of Kamchatka are considered for the first time. The Kamchatka Current in the Olyutorsky Bay contains anticyclonic eddies having a cold core of low salinity with the diameter to 90 km and to 120 km located south of the Avacha Bay. The characteristics of the Kamchatka Current eddies are determined using Terra and Aqua satellite data and the data of Argo buoys and surface drifters. The maximum velocity of a surface current in an eddy south of Kamchatka reaches 1 m/s. Satellite observations demonstrate that such eddies propagate in the Bering Sea from east to west to the latitude of Karaginsky Island and further to southwest to the Kamchatka Strait. The thermohaline characteristics of the eddies located in the northwestern Bering Sea and south of Kamchatka are close to each other. At the same time, during 1990–2017, in the eddy core temperature rose by 1°C and salinity decreased by 0.5 psu. Salinity anomalies at minimum temperature were significant in 1990 and 2004–2006 and were small in 1996–1998 and 2015–2016. The most probable reason for the salinity variations at minimum temperature is that the intensity of tidal mixing varies in the lunar nodal cycle.

Role of eddies in structuring the mesozooplankton composition in coastal waters of the western Bay of Bengal

The mesozooplankton community structure of a cold core eddy, moving through a coastal location (Bheemunipatnam) in the western Bay of Bengal (BoB), was studied continuously for 17 days (21st February to 8th March 2016) during Spring Intermonsoon. Vertical profiles of temperature, salinity and Chlorophyll a were measured in 1hr interval. Nutrients and dissolved oxygen were measured in every 3 hrs from 8 discrete depths. Mesozooplankton samples were collected through vertical haul (100 m depth to the surface) in 6 hrs intervals. Cluster analysis delineated the entire sampling days into 3 clusters based on temperature, salinity, anomaly of temperature and salinity in various depth layers Viz., phase I (Pre-eddy: 21st to 24th February), phase II (Core eddy: 28th February to 6th March) and phase III (Transition: 25th to 27th February and 7th to 8th March). The phase I was characterised as a comparatively warm, low saline, less nutrient and oxygenated subsurface water. During phase II, cool, nutrient-rich and oxygen deficient waters in the study location indicating the presence of a cold core eddy. Phase III is an intermediate condition between the phases I and II. Deep chlorophyll maxima (DCM) were shoaled to 23 m in Phase II from a depth of 38 m in Phase I. Mesozooplankton abundance was high during phase II (62320 No. m−2) compared to phase III (41633 No. m−2) and phase I (39510 No. m−2). Altogether 64 copepod species were identified of which, seven were dominant throughout the observation. Twelve species found as the indicator species in the core eddy condition. The high abundance of the Temora turbinata (upwelling indicator), Pleuromamma indica (low oxygen tolerant and highly central BoB reported) and occurrence of oceanic, oxygen minimum zone (OMZ) reported forms as indicator species in phase II is indicative of their entrainment from offshore by eddies. Eddy genesis and their movement tracking appear that this northeastern offshore formed cold core eddy advected to western coastal Bay of Bengal and traversing through the study site during the sampling period. Copepod species composition indicates the eddy trapped biological communities were sustained and retained in the core over a long period, and it advected over a long distance. This study is the first kind of information about northeastern offshore formed cold core eddy carries the plankton community in coastal waters of western BoB on their path and explains copepods community structure can be used as the indicator of eddy water masses.

Suppressed biological production in the coastal waters off Visakhapatnam, India under the impact of the very severe cyclonic storm Hudhud

Tropical cyclones generally enhance biological production due to the increase in nutrients input due to vertical mixing. In contrast, the very severe cyclonic storm (VSCS) Hudhud decreased primary production due to the strong stratification associated with torrential rainfall and high suspended load from the major city where the cyclone made landfall. The study region received nutrients from the cold core eddy and coastal upwelling in the offshore and inshore regions, respectively, during pre-cyclone period and the same was suppressed under the influence of cyclonic winds led to convergence by shoreward Ekman transport. The land run-off brought nutrients to the coast during cyclone Hudhud; however, their concentrations were less than that during other cyclones (Orissa supercyclone, Sidr and Phailin). Such low nutrient levels resulted from the VSCS Hudhud crossing the urban region (Visakhapatnam city) whereas other cyclones crossed the coast over fertile agricultural lands which led to high nutrients input associated with phytoplankton blooms. Therefore, the biological response to a cyclone not only depends on the intensity of the cyclone but also on the region of the land it crosses.

Development of a 3D thermohydraulic-neutronic coupling model for accident analysis in research miniature neutron source reactor (MNSR)

Abstract To accurately analyze the accidents in nuclear reactors, a thermohydraulic-neutronic coupling calculation is required to solve fluid dynamics and nuclear reactor kinetics equations in fine cells simultaneously and evaluate the local effects of neutronic and thermohydraulic parameters on each other. In the present study, a 3D thermohydraulic-neutronic coupling model is developed, validated and then applied for Isfahan MNSR (Miniature Neutron Source reactor) safety analysis. The proposed model is developed using FLUENT software and user defined functions (UDF) are applied to simulate the neutronic behavior of MNSR. The validation of the proposed model is first evaluated using 1mk reactivity insertion experiment into Isfahan MNSR core. Then, the developed coupling code is applied for a design basis accident (DBA) scenario analysis with the insertion of maximum allowed cold core reactivity of 4 mk. The results show that the proposed model is able to predict the behavior of the reactor core under normal and accident conditions with a good accuracy.

A Global Climatology of Extratropical Transition. Part I: Characteristics across Basins

AbstractThe authors present a global climatology of tropical cyclones (TCs) that undergo extratropical transition (ET). ET is objectively defined based on a TC’s trajectory through the cyclone phase space (CPS), which is calculated using storm tracks from 1979–2017 best track data and geopotential height fields from reanalysis datasets. Two reanalyses are used and compared for this purpose, the Japanese 55-yr Reanalysis and the ECMWF interim reanalysis. The results are used to study the seasonal and geographical distributions of storms undergoing ET and interbasin differences in the statistics of ET occurrence. About 50% of all TCs in the North Atlantic and the western North Pacific undergo ET. In the Southern Hemisphere, ET fractions range from about 20% in the south Indian Ocean and the Australian region to 45% in the South Pacific. In the majority of ETs, TCs become thermally asymmetric before forming a cold core. However, a substantial fraction of TCs take the reverse pathway, developing a cold core before becoming thermally asymmetric. This pathway is most common in the eastern North Pacific and the North Atlantic. Different ET pathways can be linked to different geographical trajectories and environmental settings. In ETs over warmer sea surface temperatures, TCs tend to lose their thermal symmetry while still maintaining a warm core. Landfalls by TCs undergoing ET occur 3–4 times per year in the North Atlantic and 7–10 times per year in the western North Pacific, while coastal regions in the Australian region are affected once every 1–2 years.

Atmospheric Response to Oceanic Cold Eddies West of Luzon in the Northern South China Sea

Using the compositing method, two kinds of sea surface temperature (SST) anomalies associated with mesoscale ocean eddies and their effects on the atmosphere over the northern South China Sea were investigated. We focused on Luzon cold eddies (LCEs), which form during the winter monsoon and occur repeatedly to the west of Luzon Island, where a SST front exists. Using satellite and reanalysis data, 20 LCEs from 2000–2016 were classified into two types according to their impact on the atmosphere. One type consisted of cold SST anomalies within the eddy interior; subsequent turbulent heat flux and surface wind speed decreased over the cold core, presenting a monopole pattern. The second type comprised SST anomalies on either side of the eddy, which mostly propagated along the SST front. For this type of LCEs, cyclonic eddy currents acting on the SST front led to the SST anomalies. They produced a dipole, with surface wind deceleration and acceleration over negative and positive SST anomalies, respectively, on either side of the eddy’s flank. Dynamically, for both types of LCE, a vertical mixing mechanism appeared to be responsible for the wind anomalies. Moreover, anomalous vertical circulations developed over the LCEs that extended over the whole boundary layer and penetrated into the free atmosphere, leading to an anomalous convective rain rate. Quantitatively, the surface wind speed changed linearly with SST; atmospheric anomalies related to LCEs explained 5%–14% of the total daily variance.

Seasonal and Interannual Variations of Sea Temperature Influenced by Galápagos Islands in Eastern Tropical Pacific Ocean

AbstractThe sea surface temperature and surface currents during 1993–2016 based on satellite remote sensing, along with the ocean temperature and currents during 1993–2013 from a data assimilative ocean simulation product, are analyzed to investigate the influence of the Galápagos Islands (GI) in the eastern tropical Pacific on the sea surface temperature. Variations of the cold core west of the GI are quantified by TC − TW, TC − TE, and the cold core area (CCA), where TW, TC, and TE are the sea surface temperature to the west of the cold core, in the cold core, and to the east of the GI, respectively. TC − TE and the CCA show a stronger influence of the GI in boreal fall than in spring, in contrast to TC − TW, which shows a stronger influence in spring than in fall. All three indices show weaker (stronger) GI's influence during El Niño (La Niña) years, but only CCA and TC − TE have significant correlations of −0.66 and 0.61 with the Niño3 index. Variations of TC − TW are related to that of upwelling immediately the west of the GI. Variations of TC − TE and CCA are related to that of the spatial distributions of the upper ocean temperature, the advection of temperature by the horizontal currents, specifically the north branch of the South Equatorial Current, and upwelling in the eastern tropical Pacific.