ESOP 97 Illinois Climate Network Soil Moisture Dataset 1.0 General Description This Illinois Climate Network (ICN) Soil Moisture dataset is provided as part of the GEWEX Continental-scale International Project (GCIP) Enhanced Seasonal Observing Period (ESOP) 1997. This dataset contains only soil moisture data within the ESOP 1997 area of interest (approximately 37 to 50 latitude and 85 to 99 longitude), which are collected from sites in the state of Illinois. This dataset covers the ESOP 97 time period (01 October 1996 through 31 May 1997) and is provided in the same format in which it was obtained. No additional quality control (QC) was performed on this dataset by the UCAR/Joint Office for Science Support (UCAR/JOSS). 2.0 Detailed Data Description This ICN Soil Moisture dataset consists of total soil moisture measured at 19 sites in the state of Illinois. The data are measured for the top 10 cm of the soil, and then for 20 cm layers (e.g., 10-30 cm, 30-50 cm, etc.) down to a depth of 2 meters. Vegetation at all stations is grass, except for one station at Dixon Springs with bare soil measurements which is co-located with a grass covered station. The soils at each station are characteristic of the soils in the vicinity of the sites. The soil series, family, texture, and total porosity in the top 1 meter for each site are listed in Table 2.0-1 and Table 2.0-2 below. ICN Soil Moisture station information is listed in Table 2.2-1 of section 2.2 Data Remarks. In this dataset, soil moisture was measured within grass plots using a Troxler Neutron Depth Probe and a Troxler Neutron Surface Probe. See Troxler Electronic Laboratories, 1980. Measurements were taken within 11 soil layers to a depth of 2 meters. Soil moisture in the top 10 cm was measured with the surface neutron probe containing a neutron source and counter positioned parallel to the soil surface and covered by a heavy plastic shield. Neutrons from the surface probe are reflected to the counter from the top 10 to 15 cm of soil. Soil moisture measurements from the soil layers below 10 cm were obtained by lowering a neutron source and counter into a vertical, 0.058 m diameter, aluminum tube permanently installed in the soil. The depth probe measures a spherical soil volume with a radius of 10 to 15 cm. Measurement errors are dependent upon the volumetric water content with errors less than 20 percent when soil moisture is above 10 percent of soil volume. Single point errors in moisture measurements from the top 1 meter of soil range from 6 percent to 13 percent when volumetric soil moisture is 30 percent of soil volume. Calibration of the neutron probe counts at each site are accomplished by taking soil cores on two occasions concurrent with neutron probe measurements. The cores are used to characterize the soil bulk density and volumetric water content of the sites and to establish the linear relationship between the neutron count ratio and soil water content. Volumetric water content (usually expressed in percent as the volume of water/volume of soil, or equivalently in millimeters as the depth of water in a soil column of specified depth) and porosity of the samples (expressed in millimeters as 1.0 minus the bulk density divided by 2.65) were computed from the mass water content and bulk density (Campbell, 1985). Total porosity, considered equivalent to volumetric water content at saturation, was determined by summing the equivalent depth in millimeters of the pore space over the six layers composing the top 1 meter of the soil (See Table 2.0-2). For a more detailed description of the ICN soil moisture data acquisition and instrument calibration, refer to Hollinger, 1994. Table 2.0-1 ICN Soil Series and Family Site Soil Soil Code Series Family ---------------------------------------------------------------------- BVL Flanagan/Elburn fine montmorillonitic,mesic Aquic Argiudolls fine silty,mixed,mesic Aquic Argiudolls DXB Grantsburg fine silty,mixed,mesic Typic Fragiudalfs BRW Cisne fine,montmorillonitic,Mollic Albaqualfs ORR Clarkesdale fine montmorillonitic,mesic Udollic Ochraqualfs DEK Flanagan/Drummer fine,montmorillonitic,mesic Aquic Argiudolls fine silty,mixed,mesic Typic Haplaquolls MON Muscatine fine silty,mixed,mesic Aquic Hapludolls ICC Clinton fine montmorillonitic,mesic Typic Hapludalfs LLC Ipava fine montmorillonitic,mesic Aquic Argiudolls FRM Weir fine montmorillonitic,mesic Typic Ochraqualfs SIU Parke fine silty,mixed mesic Ultic Hapludalfs OLN Bluford fine montmorillonitic,mesic Aeric Ochraqualfs FRE Dubuque fine silty,mixed,mesic Typic Hapludalfs RND Cisne fine montmorillonitic, mesic Mollic Albaqualfs STE Monee fine,illitic,mesic Mollic Ochraqualfs MTF Plainfield mixed,mesic,Typic Udipsamments OAK Rozetta fine silty,mixed,mesic Typic Hapludalfs FAI Unknown Unknown CMI Drummer fine silty,mixed,mesic Typic Haplaquolls DXG Grantsburg fine silty,mixed,mesic Typic Fragiudalfs Table 2.0-2 ICN Soil Texture and Total Porosity in top 1 meter. Site Soil Total Code Texture Porosity (mm) ---------------------------------------------------------------------- BVL silt loam 504 (for both soil families) DXB silt loam 486 BRW silt loam 504 ORR silt loam 544 DEK silt loam 515 silt clay loam (DEK for fine silty,mixed,mesic Typic Hapludalfs) MON silt loam 521 ICC silt loam 445 LLC silt loam 499 FRM silt loam 474 SIU silt loam 491 OLN silt loam 417 FRE silt loam 523 RND silt loam 467 STE silt loam 435 MTF loamy sand 446 OAK silt loam 470 FAI Unknown Unknown CMI silt clay loam 543 DXG silt loam 486 2.1 Detailed Format Description The ICN soil moisture data are provided in the format in which it was received. Each record contains data collected for a single station. The data are comma delimited, and the records are variable length. Table 2.1-1 below details the order and description of each data parameter in a record. All soil data are millimeters of water in each soil layer. Table 2.1-1 Parameters Units ---------- ----- Site Number Unitless. See Data Remarks section below. Year of Observation Local Month of Observation Local Day of Observation Local 10-30 cm depth Millimeters 30-50 cm depth Millimeters 50-70 cm depth Millimeters 70-90 cm depth Millimeters 90-110 cm depth Millimeters 110-130 cm depth Millimeters 130-150 cm depth Millimeters 150-170 cm depth Millimeters 170-190 cm depth Millimeters 190-200 cm depth Millimeters 0-10 cm depth Millimeters 2.2 Data Remarks This dataset contains only the Illinois Climate Network soil moisture data. ICN Soil Moisture station information including site name, latitude, longitude and elevation are given below in Table 2.2-1. Table 2.2-1 ICN Soil Moisture Station Information Site Site Site Latitude Longitude Elevation Number Name Code (deg N) (deg W) (meters) ----------------------------------------------------------------------- 1 Bondville BVL 40.05 88.22 213 2 Dixon Springs-Bare DXB 37.45 88.67 165 3 Brownstown BRW 38.95 88.95 177 4 Orr Center (Perry) ORR 39.80 90.83 206 5 De Kalb DEK 41.85 88.85 265 6 Monmouth MON 40.92 90.73 229 8 Peoria ICC 40.70 89.52 207 9 Springfield LLC 39.52 89.62 177 10 Belleville FRM 38.52 89.88 133 11 Carbondale SIU 37.72 89.23 137 12 Olney OLN 38.73 88.10 134 13 Freeport FRE 42.28 89.67 265 14 Rend Lake (Ina) RND 38.13 88.92 130 15 Stelle STE 40.95 88.17 213 16 Topeka MTF 40.30 89.90 152 17 Oak Run OAK 40.97 90.15 229 34 Fairfield FAI 38.38 88.38 136 81 Champaign CMI 40.08 88.23 219 82 Dixon Springs-Grass DXG 37.45 88.67 165 3.0 Quality Control Processing No additional QC was performed on this dataset by UCAR/Joint Office for Science Support (UCAR/JOSS). 4.0 References Campbell, G.S., 1985: Soil Physics with BASIC. Elsevier, 150 pp. Hollinger, S.E., S.A. Isard, 1994: A soil moisture climatology of Illinois. J. Climate, 7, 822-833. Troxler Electronic Laboratories, 1980: 3220 Series Instruction Manual. Troxler Electronic Laboratories.