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On the twist of emerging flux loops in the solar convection zone (2000)

Fan, Y. ; Gong, Donglai

Springer

Solar physics 192 (2000), S. 141-157

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ISSN: 1573-093X

Source: Springer Online Journal Archives 1860-2000

Topics: Physics

Notes: Abstract We perform numerical simulations of emerging flux loops in the solar convective envelope based on a weakly twisted thin flux tube model recently derived by Longcope and Klapper, generalizing the original formulation for the dynamics of untwisted thin flux tubes by Spruit. The generalized formulation includes the description of torsional Alfvén waves and takes into account the coupling of the writhing motion of the tube axis to the change in the flux tube twist based on the requirement of global helicity conservation of the closed thin flux tube. In this model, the twist of the thin flux tube is described by a quantity q defined as the angular rate of field-line rotation about the tube axis per unit length of the tube. We examine the evolution of twist along Ω-shaped emerging flux loops which are formed as a result of the non-linear growth of the Parker instability of toroidal magnetic flux tubes at the base of the solar convection zone. We find that: (1) In the northern hemisphere, a left-handed twist is generated in the flux tubes as a result of the right-handed tilt or writhe of the emerging loops induced by the Coriolis force. The generated twist increases with the latitude of emergence over the range from 0° to about 38° latitude, but then decreases when the emerging latitude exceeds 38°, because of a change in the preferred eruption pattern. The magnitude of the generated twist q is very small, ≲2×10−4 rad Mm−1, more than an order of magnitude smaller than the observed amplitude of twist (∼0.01 rad Mm−1) in solar active regions. (2) For a toroidal flux ring with a uniform initial twist q 0 along the ring, the twist amplitude |q| at the apex of the emerging loop decrease by a factor of about 0.67 because of the stretching of the loop, as it rises from the base of the convection zone to about 20 Mm below the photosphere, at which depth the flux tube can no longer be considered thin. However, because of the more rapid increase of the tube cross-sectional radius a with height, |qa|, which corresponds to the ratio between the azimuthal field to the axial field B θ/B l of the tube, increases by a factor of about 2.5 at the apex of the loop, as it rises over the same distance. (3) Because of the effect of the Coriolis force, the distribution of twist along the emerging loop is asymmetric between the leading (in the direction of rotation) and the following sides of the loop. Both |q| and |qa| are greater at the following side than the leading at any depth. Based on the evolution of twist along emerging flux loops, we discuss possible constraints on the twist q 0 of initial toroidal flux tubes at the base of the convection zone.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1005260207672

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Water stable isotopes and associated salinity measurements in the Canadian Arctic Archipelago from 17 July – 04 August 2019 (2021)

Garcia-Eidell, Cynthia ; Berkelhammer, Max ; Bellagamba, Anthony ; [et al.]

PANGAEA

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Publication Date: 2023-12-31

Description: The relationship between δ¹⁸O and salinity has been widely studied because it can provide crucial information on the partitioning of isotopes through the hydrological cycle. Current understanding of δ¹⁸O-S characteristics has been used to constrain water cycle models, isotope-enabled atmospheric and ocean models as well as to monitor evaporation (E) and precipitation (P) changes in major ocean basins. However, in the polar regions, where large spatial and temporal variabilities in δ¹⁸O and salinity are expected due to the highly seasonal sea ice melting/formation, river runoff, E-P intensification and rapidly changing summer ice minimum, uncertainties still surround the δ¹⁸O-Salinity relationship. To observe the inputs of freshwater in a poorly-understood, but vastly changing region in the Arctic, we collected matching δ¹⁸O-Salinity data from discrete samples from the surface (bucket sampling) and from profiles (Conductivity, Temperature, Depth (CTD) casts) in the Canadian Arctic Archipelago (CAA) during the Northwest Passage expedition aboard the RV Oden last 17 July – 04 August 2019. Matching δ¹⁸O-Salinity measurements were also obtained from ice core samples as well as from a precipitation event during the cruise. Here, we present more than 200 new and paired δ¹⁸O-Salinity measurements to help represent water mass end-members for freshwater budgeting as well as understanding the changes in the CAA's hydrologic cycle.

Keywords: CTD profile; ice core isotopes; Northwest Passage Project; NPP; precipitation isotopes; Salinity; surface salinity; water stable isotopes

Type: Dataset

Format: application/zip, 4 datasets

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Precipitation stable isotopes (¹⁸O and D) and salinity in the Canadian Arctic Archipelago in the summer of 2019 (2021)

Garcia-Eidell, Cynthia ; Berkelhammer, Max ; Bellagamba, Anthony ; [et al.]

PANGAEA

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Publication Date: 2023-12-31

Description: This data contains one (1) geolocated water stable isotope measurement from one (1) rain event on 29 July 2019. Shipboard rain samples were collected in a separatory funnel filled with a layer of mineral oil to prevent evaporation. Water samples were transferred to a 30-mL Nalgene bottles that were filled to the brim. Bottles were tightly closed, sealed with parafilm, and placed inside sampling bags. It was then transported to the Atmosphere, Climate, and Ecosystems lab at the University of Illinois at Chicago for processing. The δ¹⁸O and dD were measured using a Picarro l2130-I CRDS water isotope analyzer with a wire mesh inserted in the vaporizer inlet. Fifteen injections were made for each sample and necessary corrections to address 'memory effect' were employed. Measurements were normalized using the dD and δ¹⁸O values of internal water standards. Header includes event, latitude, longitude, sampling date, campaign, sampling method, location, isotope analyzer, ¹⁸O values (‰) and D values (‰).

Keywords: CAA; Canadian Arctic Archipelago; Date/Time of event; Isotope analyzer L2130-i, Picarro Inc.; Latitude of event; Longitude of event; Northwest Passage Project; NPP; NPP19precip; Oden; Oden1907; precipitation isotopes; RAIN; Rain water collector; Salinity; water stable isotopes; δ18O, water; δ Deuterium, water

Type: Dataset

Format: text/tab-separated-values, 2 data points

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Surface water stable isotopes (¹⁸O and D) and salinity in the Canadian Arctic Archipelago in the summer of 2019 (2021)

Garcia-Eidell, Cynthia ; Berkelhammer, Max ; Bellagamba, Anthony ; [et al.]

PANGAEA

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Publication Date: 2023-12-31

Description: This data contains 63 geolocated water stable isotopes and salinity measurements from the surface of the ocean along the RV Oden cruise track. Surface seawater sampling was conducted using bucket sampling. This was done by throwing a weighted bucket offboard to sample the surface of the ocean every six (6) hours. Chosen times were 5:00, 11:00, 17:00, and 23:00. Multiple readings of sea surface salinity were recorded using a YSI professional series digital probe per sampling Water samples were transferred to a 30-mL Nalgene bottles that were filled to the brim. Bottles were tightly closed, sealed with parafilm, and placed inside sampling bags. Two samples were collected per sampling point, and all measurements were geolocated. A total of 126 samples were collected from 19 July – 04 August 2019. All water samples were transported to the Atmosphere, Climate, and Ecosystems lab at the University of Illinois at Chicago for processing. The δ¹⁸O and dD were measured using a Picarro l2130-I CRDS water isotope analyzer with a wire mesh inserted in the vaporizer inlet to trap salt from the seawater. Fifteen injections were made for each sample and necessary corrections to address 'memory effect' were employed. Measurements were normalized using the dD and δ¹⁸O values of internal water standards. Data table header includes the event, latitude, longitude, sampling date, campaign, sampling method, location, isotope analyzer model, salinity sensor, ¹⁸O values (‰), D values (‰), and salinity values (psu).

Keywords: BUCKET; Bucket water sampling; CAA; Canadian Arctic Archipelago; Date/Time of event; Event label; Isotope analyzer L2130-i, Picarro Inc.; Latitude of event; Longitude of event; Northwest Passage Project; NPP; NPP19surface_station_1; NPP19surface_station_10; NPP19surface_station_11; NPP19surface_station_12; NPP19surface_station_13; NPP19surface_station_14; NPP19surface_station_15; NPP19surface_station_16; NPP19surface_station_17; NPP19surface_station_18; NPP19surface_station_19; NPP19surface_station_2; NPP19surface_station_20; NPP19surface_station_21; NPP19surface_station_22; NPP19surface_station_23; NPP19surface_station_24; NPP19surface_station_25; NPP19surface_station_26; NPP19surface_station_27; NPP19surface_station_28; NPP19surface_station_29; NPP19surface_station_3; NPP19surface_station_30; NPP19surface_station_31; NPP19surface_station_32; NPP19surface_station_33; NPP19surface_station_34; NPP19surface_station_35; NPP19surface_station_36; NPP19surface_station_37; NPP19surface_station_38; NPP19surface_station_39; NPP19surface_station_4; NPP19surface_station_40; NPP19surface_station_41; NPP19surface_station_42; NPP19surface_station_43; NPP19surface_station_44; NPP19surface_station_45; NPP19surface_station_46; NPP19surface_station_47; NPP19surface_station_48; NPP19surface_station_49; NPP19surface_station_5; NPP19surface_station_50; NPP19surface_station_51; NPP19surface_station_52; NPP19surface_station_53; NPP19surface_station_54; NPP19surface_station_55; NPP19surface_station_56; NPP19surface_station_57; NPP19surface_station_58; NPP19surface_station_59; NPP19surface_station_6; NPP19surface_station_60; NPP19surface_station_61; NPP19surface_station_62; NPP19surface_station_63; NPP19surface_station_7; NPP19surface_station_8; NPP19surface_station_9; Oden; Oden1907; Salinity; surface salinity; water stable isotopes; YSI Professional Plus Multiparameter Instrument; YSI Pro Plus; δ18O, water; δ Deuterium, water

Type: Dataset

Format: text/tab-separated-values, 189 data points

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Ice core water stable isotopes (¹⁸O and D) and salinity in the Canadian Arctic Archipelago in the summer of 2019 (2021)

Garcia-Eidell, Cynthia ; Berkelhammer, Max ; Bellagamba, Anthony ; [et al.]

PANGAEA

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Publication Date: 2023-12-31

Description: This data contains ten (10) geolocated water stable isotopes and salinity measurements from three (3) sea ice cores collected during the cruise. Sea ice core sampling was conducted for three (3) ice coring stations. A sea ice core drill was used to collect the cores. Total length of each core was recorded as well as the temperature per 10 cm interval. The cores were then sectioned per 20 cm and the sections were thawed in different Marvin bottles. Once thawed, multiple water salinity measurements were taken using a YSI professional series digital probe. Water samples were transferred to a 30-mL Nalgene bottles that were filled to the brim. Bottles were tightly closed, sealed with parafilm, and placed inside sampling bags. A total of ten (10) samples were collected from the ice core collected. All water samples were transported to the Atmosphere, Climate, and Ecosystems lab at the University of Illinois at Chicago for processing. The δ¹⁸O and dD were measured using a Picarro l2130-I CRDS water isotope analyzer with a wire mesh inserted in the vaporizer inlet to trap salt from the seawater. Fifteen injections were made for each sample and necessary corrections to address 'memory effect' were employed. Measurements were normalized using the dD and δ¹⁸O values of internal water standards. Header includes following details: event, core segment (cm), latitude, longitude, sampling date, campaign, sampling method, location, isotope analyzer, salinity sensor, ¹⁸O values (‰), D values (‰), salinity values (psu).

Keywords: CAA; Canadian Arctic Archipelago; Date/Time of event; Depth, bottom/max; DEPTH, ice/snow; Depth, top/min; Event label; ice core isotopes; Ice drilling corer (Kovacs); Isotope analyzer L2130-i, Picarro Inc.; Latitude of event; Longitude of event; Northwest Passage Project; NPP; NPP19icecore_station_2; NPP19icecore_station_4; NPP19icecore_station_5; Oden; Oden1907; Salinity; water stable isotopes; YSI Professional Plus Multiparameter Instrument; YSI Pro Plus; δ18O, water; δ Deuterium, water

Type: Dataset

Format: text/tab-separated-values, 74 data points

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Water column stable isotopes (¹⁸O and D), salinity, and temperature in the Canadian Arctic Archipelago in the summer of 2019 (2021)

Garcia-Eidell, Cynthia ; Berkelhammer, Max ; Bellagamba, Anthony ; [et al.]

PANGAEA

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Publication Date: 2024-02-27

Description: This data contains 125 geolocated water stable isotope, salinity, and temperature measurements from niskin bottle samples at varying depths from 52 Conductivity, Temperature, Depth (CTD) casts along the RV Oden cruise track. The CTD rosette water sampling was conducted following the CLIVAR/GO-SHIP protocol with a 'water cop' keeping track of the sampling order. Sampling for gases goes first, followed by nutrients, water stable isotopes, and then microbiological and DNA sampling during each cast. Samples for water stable isotopes analyses were collected by filling 30-mL Nalgene bottles to the brim. Bottles were closed tightly, sealed with parafilm, and stored in a labeled sample bag. Sampling depths chosen were based on the profile, location, and whether samples were collected for nutrients. Two samples were collected per depth. A total of 250 samples were collected from the 52 CTD casts from 19 July – 04 August 2019. The corresponding salinity and temperature measurements per sampling depth were collected from the CTD data. All water samples were transported to the Atmosphere, Climate, and Ecosystems lab at the University of Illinois at Chicago for processing. The δ¹⁸O and dD were measured using a Picarro l2130-I CRDS water isotope analyzer with a wire mesh inserted in the vaporizer inlet to trap salt from the seawater. Fifteen injections were made for each sample and necessary corrections to address 'memory effect' were employed. Measurements were normalized using the dD and δ¹⁸O values of internal water standards. Data table header includes the event, depth (m) latitude, longitude, sampling date, campaign, sampling method, location, isotope analyzer, salinity and temperature sensor, ¹⁸O values (‰), D values (‰), salinity values (psu), and temperature values (°C).

Keywords: CAA; Canadian Arctic Archipelago; CTD; CTD, Sea-Bird SBE 911plus; CTD profile; Date/Time of event; DEPTH, water; Event label; Isotope analyzer L2130-i, Picarro Inc.; Latitude of event; Longitude of event; Northwest Passage Project; NPP; NPP19profile_station_1; NPP19profile_station_10; NPP19profile_station_11; NPP19profile_station_12; NPP19profile_station_13; NPP19profile_station_14; NPP19profile_station_15; NPP19profile_station_16; NPP19profile_station_18; NPP19profile_station_19; NPP19profile_station_2; NPP19profile_station_20; NPP19profile_station_21; NPP19profile_station_23; NPP19profile_station_24; NPP19profile_station_25; NPP19profile_station_26; NPP19profile_station_27; NPP19profile_station_28; NPP19profile_station_29; NPP19profile_station_30; NPP19profile_station_31; NPP19profile_station_32; NPP19profile_station_34; NPP19profile_station_35; NPP19profile_station_36; NPP19profile_station_39; NPP19profile_station_40; NPP19profile_station_41; NPP19profile_station_43; NPP19profile_station_45; NPP19profile_station_46; NPP19profile_station_5; NPP19profile_station_51; NPP19profile_station_52; NPP19profile_station_6; NPP19profile_station_7; NPP19profile_station_8; NPP19profile_station_9; Oden; Oden1907; Salinity; Temperature, water; water stable isotopes; δ18O, water; δ Deuterium, water

Type: Dataset

Format: text/tab-separated-values, 500 data points

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Bacterial and archaeal specific-predation in the North Atlantic Basin (2019)

Seyler, Lauren M. ; Tuorto, Steve ; McGuinness, Lora R. ; [et al.]

Frontiers Media

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Publication Date: 2022-10-26

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seyler, L. M., Tuorto, S., McGuinness, L. R., Gong, D., & Kerkhof, L. J. Bacterial and archaeal specific-predation in the North Atlantic Basin. Frontiers in Marine Science, 6, (2019): 555, doi:10.3389/fmars.2019.00555.

Description: Stable isotope probing (SIP) was used to track prokaryotic and eukaryotic carbon uptake along a meridional transect (Long. 52°W) in the North Atlantic to assess if 13C-resource partitioning between bacteria and archaea and 13C-labeled eukaryotic predators could be detected. One-liter SIP microcosms were amended with 13C-acetate or 13C-urea and incubated for 48 h. Our data indicated archaea often outcompeted bacteria for 13C-urea while both archaea and bacteria could incorporate 13C-acetate. This 13C label could also be tracked into eukaryotic microbes. The largest number of 13C-labeled eukaryotic OTUs, and the greatest percentage of eukaryotic 13C signal, were observed in conjunction with both archaeal and bacterial 13C incorporation, suggesting that most eukaryotic predators do not distinguish between archaeal and bacterial prey. However, other 13C-eukaryotic OTUs were exclusively associated with either 13C-archaeal or 13C-bacterial OTUs. These archaeal-specific and bacterial-specific 13C-eukaryotic OTUs were related to known bactivorous predators including Ancyromonas, Amastigomonas, Cafeteria, and Caecitellus. Our SIP findings suggest both resource partitioning between bacteria and TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota) archaea and selective predation by eukaryotic predators. Determining the equalizing mechanisms for co-existence in the marine environment can help map predator/prey interactions to better estimate carbon flow in the deep ocean.

Description: This research was made possible through the support of the U.S Global Ocean Carbon and Repeat Hydrography Program and NSF Ocean Technology and Interdisciplinary Program grant (#1131022) to LK.

Keywords: Archaea ; Bacteria ; Predation ; Competition ; Stable isotope probing ; Deep ocean

Repository Name: Woods Hole Open Access Server

Type: Article

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Shear turbulence in the high-wind Southern Ocean using direct measurements (2022)

Ferris, Laur ; Gong, Donglai ; Clayson, Carol A. ; [et al.]

American Meteorological Society

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Publication Date: 2022-10-12

Description: Author Posting. © American Meteorological Society, 2022. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 52(10), (2022): 2325–2341, https://doi.org/10.1175/jpo-d-21-0015.1.

Description: The ocean surface boundary layer is a gateway of energy transfer into the ocean. Wind-driven shear and meteorologically forced convection inject turbulent kinetic energy into the surface boundary layer, mixing the upper ocean and transforming its density structure. In the absence of direct observations or the capability to resolve subgrid-scale 3D turbulence in operational ocean models, the oceanography community relies on surface boundary layer similarity scalings (BLS) of shear and convective turbulence to represent this mixing. Despite their importance, near-surface mixing processes (and ubiquitous BLS representations of these processes) have been undersampled in high-energy forcing regimes such as the Southern Ocean. With the maturing of autonomous sampling platforms, there is now an opportunity to collect high-resolution spatial and temporal measurements in the full range of forcing conditions. Here, we characterize near-surface turbulence under strong wind forcing using the first long-duration glider microstructure survey of the Southern Ocean. We leverage these data to show that the measured turbulence is significantly higher than standard shear-convective BLS in the shallower parts of the surface boundary layer and lower than standard shear-convective BLS in the deeper parts of the surface boundary layer; the latter of which is not easily explained by present wave-effect literature. Consistent with the CBLAST (Coupled Boundary Layers and Air Sea Transfer) low winds experiment, this bias has the largest magnitude and spread in the shallowest 10% of the actively mixing layer under low-wind and breaking wave conditions, when relatively low levels of turbulent kinetic energy (TKE) in surface regime are easily biased by wave events.

Description: This paper is VIMS Contribution 4103. Computational resources were provided by the VIMS Ocean-Atmosphere and Climate Change Research Fund. AUSSOM was supported by the OCE Division of the National Science Foundation (1558639).

Keywords: Turbulence ; Wind shear ; Boundary layer ; Parameterization

Repository Name: Woods Hole Open Access Server

Type: Article

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