bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arctic Sea Ice and Freshwater Changes Driven by the Atmospheric Leading Mode in a Coupled Sea Ice–Ocean Model
Authors: Zhang Xiangdong , Ikeda Moto , Walsh John E. 
Published: June 2003

AbstractObservational and modeling studies have indicated recent large changes of sea ice and hydrographic properties in the Arctic Ocean. However, the observational database is sufficiently sparse that the mechanisms responsible for the recent changes are not fully understood. A coupled Arctic ocean–sea ice model forced by output from the NCEP–NCAR reanalysis is employed to investigate the role that the leading atmospheric mode has played in the recent changes of the Arctic Ocean. A modified Arctic Oscillation (AO) index is derived for the region poleward of 62.5°N in order to avoid ambiguities in the distinction between the conventional AO and the North Atlantic Oscillation index. The model results indicate that the AO is the driver of many of the changes manifested in the recent observations. The model shows reductions of Arctic sea ice area and volume by 3.2% and 8.8%, respectively, when the AO changes from its negative to its positive phase. Concurrently, freshwater storage decreases by about 2%, while the sea ice and freshwater exports via Fram Strait increase substantially. The changes of sea ice and freshwater storage are strikingly asymmetric between the east and the west Arctic. Notable new findings include 1) the interaction of the dynamic and thermodynamic responses in the sense that changes of sea ice growth and melt are driven by, and feed back negatively to, the dynamically (transport) driven changes of sea ice volume; and 2) the compatibility of the associated freshwater changes with recently observed changes in the salinity of the upper Arctic Ocean, thereby explaining the observed salinity variations by a mechanism that is distinct from, but complementary to, the altered circulation of Siberian river water. In addition, the enhanced freshwater export could be a contributing factor to the increased salinity in the Arctic Ocean. The results of the simulations indicate that Arctic sea ice and freshwater distributions change substantially if one phase of the AO predominates over a decadal timescale. However, such results are based on an idealization of the real-world situation, in which the pattern of forcing varies interannually and the number of positive-AO years varies among decades.
Interannual Variability of the Western North Pacific Summer Monsoon: Differences between ENSO and Non-ENSO Years
Authors: Chou Chia , Tu Jien-Yi , Yu Jia-Yuh 
Published: June 2003

Abstract
The interannual variability of the western North Pacific (WNP) summer monsoon is examined for the non-ENSO, ENSO developing, and ENSO decaying years, respectively. The ENSO developing (decaying) year is defined as the year before (after) the mature phase of ENSO, and the non-ENSO year is defined as the year that is neither the ENSO developing year nor the ENSO decaying year. A strong (weak) WNP summer monsoon tends to occur during the El Niño (La Niña) developing year and a weak (strong) WNP summer monsoon tends to occur during the El Niño (La Niña) decaying year. In all non-ENSO, ENSO developing, and ENSO decaying years, the strong (weak) WNP summer monsoon is associated with the positive (negative) rainfall anomalies, cold (warm) sea surface temperature anomalies, warm (cold) upper-tropospheric temperature anomalies, low (high) surface pressure anomalies, and a low-level cyclonic (anticyclonic) circulation anomaly over the subtropical WNP. The 850-hPa wave train associated with the WNP and east Asian (EA) summer monsoons in the non-ENSO, ENSO developing, and ENSO decaying years extends northward and suggests a possible teleconnection between the WNP summer monsoon and the North American climate. The wave train extended into the Southern Hemisphere in the non-ENSO and ENSO developing years implies a teleconnection between the WNP summer monsoon and the Australian winter climate. The anomalous WNP monsoon in the non-ENSO and ENSO developing years exists only in summer, while the anomalous WNP monsoon in the ENSO decaying year persists from the beginning of the year to the summer season. The anomalous WNP summer monsoon exhibits a strong ocean–atmosphere interaction, especially in the ENSO decaying year. This study suggests that the anomalous WNP summer monsoon in the non-ENSO year is associated with the variation of the meridional temperature gradient in the upper troposphere, while the anomalous WNP summer monsoon in the ENSO developing and decaying years is associated with ENSO-related SST anomalies.
Effect of Exclusion of Anomalous Tropical Stations on Temperature Trends from a 63-Station Radiosonde Network, and Comparison with Other Analyses
Authors: Angell James K. 
Published: June 2003

Abstract
A 63-station radiosonde network has been used for many years to estimate temperature variations and trends at the surface and in the 850–300-, 300–100-, and 100–50-mb layers of climate zones, both hemispheres, and the globe, but with little regard for the quality of individual station data. In this paper, nine tropical radiosonde stations in this network are identified as anomalous based on unrepresentatively large standard-error-of-regression values for 300–100-mb trends for the period 1958–2000. In the Tropics the exclusion of the 9 anomalous stations from the 63-station network for 1958–2000 results in a warming of the 300–100-mb layer rather than a cooling, a doubling of the warming of the 850–300-mb layer to a value of 0.13 K decade−1, and a greater warming at 850–300-mb than at the surface. The global changes in trend are smaller, but include a change to the same warming of the surface and the 850–300-mb layer during 1958–2000. The effect of the station exclusions is much less for 1979–2000, suggesting that most of the data problems are before this time. Temperature trends based on the 63-station network are compared with the Microwave Sounding Unit (MSU) and other radiosonde trends, and agreement is better after the exclusion of the anomalous stations. There is consensus that in the Tropics the troposphere has warmed slightly more than the surface during 1958–2000, but that there has been a warming of the surface relative to the troposphere during 1979–2000. Globally, the warming of the surface and the troposphere are essentially the same during 1958–2000, but during 1979–2000 the surface warms more than the troposphere. During the latter period the radiosondes indicate considerably more low-stratospheric cooling in the Tropics than does the MSU.
Coupled Ocean–Atmosphere Dynamical Processes in the Tropical Indian and Pacific Oceans and the TBO
Authors: Meehl Gerald A. , Arblaster Julie M. , Loschnigg Johannes 
Published: June 2003

Abstract
The transitions (from relatively strong to relatively weak monsoon) in the tropospheric biennial oscillation (TBO) occur in northern spring for the south Asian or Indian monsoon and northern fall for the Australian monsoon involving coupled land–atmosphere–ocean processes over a large area of the Indo-Pacific region. Transitions from March–May (MAM) to June–September (JJAS) tend to set the system for the next year, with a transition to the opposite sign the following year. Previous analyses of observed data and GCM sensitivity experiments have demonstrated that the TBO (with roughly a 2–3-yr period) encompasses most ENSO years (with their well-known biennial tendency). In addition, there are other years, including many Indian Ocean dipole (or zonal mode) events, that contribute to biennial transitions. Results presented here from observations for composites of TBO evolution confirm earlier results that the Indian and Pacific SST forcings are more dominant in the TBO than circulation and meridional temperature gradient anomalies over Asia. A fundamental element of the TBO is the large-scale east–west atmospheric circulation (the Walker circulation) that links anomalous convection and precipitation, winds, and ocean dynamics across the Indian and Pacific sectors. This circulation connects convection over the Asian–Australian monsoon regions both to the central and eastern Pacific (the eastern Walker cell), and to the central and western Indian Ocean (the western Walker cell). Analyses of upper-ocean data confirm previous results and show that ENSO El Niño and La Niña events as well as Indian Ocean SST dipole (or zonal mode) events are often large-amplitude excursions of the TBO in the tropical Pacific and Indian Oceans, respectively, associated with anomalous eastern and western Walker cell circulations, coupled ocean dynamics, and upper-ocean temperature and heat content anomalies. Other years with similar but lower-amplitude signals in the tropical Pacific and Indian Oceans also contribute to the TBO. Observed upper-ocean data for the Indian Ocean show that slowly eastward-propagating equatorial ocean heat content anomalies, westward-propagating ocean Rossby waves south of the equator, and anomalous cross-equatorial ocean heat transports contribute to the heat content anomalies in the Indian Ocean and thus to the ocean memory and consequent SST anomalies, which are an essential part of the TBO.
GPCP Pentad Precipitation Analyses: An Experimental Dataset Based on Gauge Observations and Satellite Estimates
Authors: Xie Pingping , Janowiak John E. , Arkin Phillip A. , Adler Robert , Gruber Arnold , Ferraro Ralph , Huffman George J. , Curtis Scott 
Published: June 2003

Abstract
As part of the Global Precipitation Climatology Project (GPCP), analyses of pentad precipitation have been constructed on a 2.5° latitude–longitude grid over the globe for a 23-yr period from 1979 to 2001 by adjusting the pentad Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) against the monthly GPCP-merged analyses. This adjustment is essential because the precipitation magnitude in the pentad CMAP is not consistent with that in the monthly CMAP or monthly GPCP datasets primarily due to the differences in the input data sources and merging algorithms, causing problems in applications where joint use of the pentad and monthly datasets is necessary. First, pentad CMAP-merged analyses are created by merging several kinds of individual data sources including gauge-based analyses of pentad precipitation, and estimates inferred from satellite observations. The pentad CMAP dataset is then adjusted by the monthly GPCP-merged analyses so that the adjusted pentad analyses match the monthly GPCP in magnitude while the high-frequency components in the pentad CMAP are retained. The adjusted analyses, called the GPCP-merged analyses of pentad precipitation, are compared to several gauge-based datasets. The results show that the pentad GPCP analyses reproduced spatial distribution patterns of total precipitation and temporal variations of submonthly scales with relatively high quality especially over land. Simple applications of the 23-yr dataset demonstrate that it is useful in monitoring and diagnosing intraseasonal variability. The Pentad GPCP has been accepted by the GPCP as one of its official products and is being updated on a quasi-real-time basis.
Comparative Influence of Snow and SST Variability on Extratropical Climate in Northern Winter
Authors: Kumar Arun , Yang Fanglin 
Published: June 2003

Abstract
In this study the influence of snow on atmospheric seasonal mean variability in the extratropical latitudes during boreal winter was studied. The motivation for this analysis was to understand the characteristics of low-frequency atmospheric variability in the extratropical latitudes, and to assess if the interannual variations in snow could lead to potential predictability on seasonal timescales. The influence of snow on atmospheric variability was assessed from a suite of atmospheric general circulation model (GCM) simulations where snow depth amount was either prescribed to a seasonally varying climatology, or was allowed to evolve during the model integration. Further, the influence of snow variability was contrasted with the influence of interannual variability in sea surface temperatures (SSTs) on the atmospheric flow.
A systematic influence of snow variability on the atmospheric seasonal mean variability was found. For example, for the GCM simulations in which snow amount and its extent were allowed to evolve freely, the interannual variability of surface air temperature was found to be larger. The influence of snow variability, however, was confined to the lower troposphere, and little change in the interannual variability of upper-tropospheric circulation, for example, 200-hPa heights, occurred. This bottom-up vertical structure of the influence of snow on the atmospheric variability was in contrast to the top-down influence of tropical SST variability on the extratropical flow.
The cause for the enhancement of atmospheric variability in the lower troposphere was argued to be related to the dependence of surface albedo on snow depth amount. This dependence was such that the interaction between the atmospheric variability and the underlying snow could be viewed as a positive feedback process whereby surface temperature anomalies amplify even further.
Enhanced Seasonal Rainfall in Northern Venezuela and the Extreme Events of December 1999
Authors: Lyon Bradfield 
Published: June 2003

Abstract
Torrential rainfall during December 1999 resulted in devastating floods and landslides along the northern coast of Venezuela. These events occurred in an area with a predominantly dry climate, took place during what is regionally the dry season, and were preceded by unusually heavy seasonal rainfall. An observational study was undertaken in an attempt to identify anomalous features of the climate system associated with both the enhanced seasonal rainfall prior to the landslides as well as the extreme December rainfall events that triggered them. Observational data for the period 1950–99 are used to provide historical context. Results indicate that the copious seasonal rainfall prior to the floods was associated with anomalous conditions in both the tropical Pacific and Atlantic basins similar to past events, although some features were unusually strong in 1999. The extreme daily rainfall in December 1999 was associated with atmospheric circulation features originating in the extratropical Northern Hemisphere that penetrated unusually far into the Tropics. Possible physical mechanisms acting to enhance rainfall on both timescales are discussed.
Using Mean Flow Change as a Proxy to Infer Interdecadal Storm Track Variability
Authors: Chang Edmund K. M. , Fu Yunfei 
Published: June 2003

Abstract
Several recent studies, based mainly on analyses of reanalysis data, have suggested that the Northern Hemisphere storm tracks have intensified during the second half of the twentieth century. However, comparisons with rawinsonde observations over land areas suggest that eddy variance/covariance statistics may contain spurious jumps that had led to an exaggeration of the storm track secular trend. In this study, storm track variations are inferred from mean flow anomalies using canonical correlation analysis (CCA). A CCA model relating storm track anomalies to mean flow anomalies is derived using recent, more reliable data. The model is then applied to infer storm track anamalies using mean flow anomalies for earlier periods, when storm track analyses are deemed more suspect (or even nonexistent).
Results of the CCA analyses suggest that the strong secular trend observed over the Atlantic basin and Europe is consistent with mean flow anomalies, while CCA predictions based on mean flow changes suggest only a much weaker trend in the Pacific storm track activity than that present in the reanalysis data. Over the regions where comparisons with rawinsonde data can be made, the interdecadal trends inferred by the CCA model are quite consistent with rawinsonde data over the Pacific storm track entrance and exit regions, as well as the Atlantic storm track exit regions, but are inconsistent with rawinsonde observations and reanalysis data over northeastern North America, where CCA predictions are generally poor.
A CCA hindcast based on Trenberth and Paolino mean sea level pressure data as a predictor shows no indication that the secular increase in storm track intensity extends further back prior to 1960, suggesting that during the entire twentieth century, storm track activity was weakest during the 1960s.
Equatorial Atlantic Rain Frequency: An Intercentennial Comparison
Authors: Short David A. 
Published: June 2003

AbstractAnalyses of the frequency of rain occurrence over the equatorial Atlantic Ocean from two sources are compared: a nineteenth-century journal publication based on ship's logbook entries, and a 3-yr average, 1998–2000, of observations from the precipitation radar aboard the Tropical Rainfall Measuring Mission satellite observatory. The sources agree remarkably well on the position and shape of the equatorial maximum, with a correlation coefficient of 0.99. However, the magnitudes differ by about a factor of 2, with the modern estimate being lower. This disparity is likely to be attributable to characteristics of the observing systems. The radar sensitivity and scanning characteristics combine to underestimate rain occurrence. The precise nature of the nineteenth-century sources are not documented; however, they almost certainly have been incorporated into the Comprehensive Ocean–Atmosphere Data Set (COADS).
Design and Control of a Chained Form Manipulator
Authors: Chung Woojin , Nakamura Yoshihiko 
Published: June 2003

Exploiting unique features of nonholonomic systems, innovative and advantageous mechanisms can be designed. We have proposed a nonholonomic manipulator which is a controllable n joint manipulator with only two actuators. In order to create its nonholonomic constraint, a special type of velocity transmission, called the non-holonomic gear, was developed. There are many possible alternatives for designing underactuated manipulators using the nonholonomic gear. In this paper, the chained form manipulator is designed not only to satisfy chained form convertibility, but also to achieve control simplicity. Design requirements are clarified, then we establish the mechanical design of the chained form manipulator. The chained form manipulator is designed with an innovative main power train as well as nonholonomic gears. For experimental verification, a prototype is fabricated. So far, various control strategies for nonholonomic systems have been proposed. In this paper, an efficient motion planning scheme for the chained form is presented to approximate any holonomic path with the feasible nonholonomic path. Furthermore, a new concept of motion planning is proposed through the analysis of the initial-condition sensitivity. Combining these two approaches, the motion planning scheme is constructed towards practical applications. Presented experimental results show the usefulness of the design and the applied control scheme.
The multidrug resistance-associated protein 3 (MRP3) is associated with a poor outcome in childhood ALL and may account for the worse prognosis in male patients and T-cell immunophenotype
Authors: Steinbach Daniel , Wittig Susann , Cario Gunnar , Viehmann Susanne , Mueller Angelika , Gruhn Bernd , Haefer Ralf , Zintl Felix , Sauerbrey Axel 
Published: June 2003

AbstractThe family of multidrug resistance-associated proteins (MRPs) belongs to the superfamily of adenosine triphosphate-binding-cassette (ABC) transporters, which have the ability to function as outward pumps for chemotherapeutic drugs and therefore might be involved in drug resistance. In this study the expression of the MRP2, MRP3, MRP4, MRP5, and SMRP genes was measured using TaqMan real-time polymerase chain reaction (PCR) in 103 children with previously untreated acute lymphoblastic leukemia (ALL) (precursor B-cell ALL [B-ALL], n = 71; T-cell ALL [T-ALL], n = 32). All 5 genes were expressed with a great variability. Only MRP3 expression was associated with a significantly worse prognosis (P = .008). The median expression of MRP3 was 10-fold higher in T-ALL than in precursor B-ALL (P &lt; .001) and 4-fold higher in male patients than in female patients (P &lt; .001). The prognostic impact of MRP3 was independent of immunophenotype or sex. Higher levels of MRP3 were found in patients with a poor in vivo response to prednisone, but this could not be confirmed in an independent case-control study (40 patients) for prednisone response. In healthy donors, the median expression of MRP4 was 4-fold higher in bone marrow and 8-fold higher in CD34+ stem cells compared with peripheral blood (P = .002). Our results suggest that MRP3 is involved in drug resistance in childhood ALL. It therefore represents an interesting target to overcome multidrug resistance. High levels of MRP3 could possibly be the reason for the poorer prognosis of male patients or patients who have T-ALL. Similar to other members of the family of ABC transporters, MRP4 seems to be a marker for immature stem cells. (Blood. 2003;102:4493-4498)
A novel EVI1 gene family, MEL1, lacking a PR domain (MEL1S) is expressed mainly in t(1;3)(p36;q21)-positive AML and blocks G-CSF–induced myeloid differentiation
Authors: Nishikata Ichiro , Sasaki Hidenori , Iga Mutsunori , Tateno Yoko , Imayoshi Suzuko , Asou Norio , Nakamura Takuro , Morishita Kazuhiro 
Published: June 2003

AbstractWe have identified a novel gene MEL1 (MDS1/EVI1-like gene 1) encoding a zinc finger protein near the breakpoint of t(1; 3)(p36;q21)-positive human acute myeloid leukemia (AML) cells. Here, we studied the structure, expression pattern, and function of MEL1 in leukemia cells. In this study, we have identified 3 transcription start sites, 1 in exon 1 and 2 in exon 2, and 2 kinds of translation products, 170 kDa (MEL1) and 150 kDa (MEL1S). Notably, the 150-kDa band of MEL1S was detected mainly in the t(1;3)(p36;q21)-positive AML cells. By immunoblot analysis and proteolytic mapping, it is suggested that the 150-kDa band of MEL1S in the leukemia cells is translated from the internal initiation codon ATG597 in exon 4 and is mostly lacking the amino-terminal PR domain of MEL1. By the cyclic amplification and selection of targets (CASTing) method for identifying consensus sequences, it was shown that the consensus sequences of MEL1 were included in 2 different consensus sequences for DNA-binding domain 1 and 2 (D1-CONS and D2-CONS) of EVI1. In reporter gene assays, MEL1S activated transcription via binding to D2-CONS; however, the fusion of MEL1 or MEL1S to GAL4 DNA-binding domain (DBD) made them GAL4 binding site–dependent transcriptional repressors. Moreover, overexpression of MEL1S blocked granulocytic differentiation induced by granulocyte colony-stimulating factor (G-CSF) in interleukin-3 (IL-3)–dependent murine myeloid L-G3 cells, while MEL1 could not block the differentiation. Thus, it is likely that overexpression of the zinc finger protein lacking the PR domain (EVI1 and MEL1S) in the leukemia cells is one of the causative factors in the pathogenesis of myeloid leukemia.