Noise Levels at Different Periods
The table below gives the decibel 10% noise level (in db) for each month in
several period bands. The 10% noise level is defined as the signal
level not exceeded 10% of the time, based on hourly measurements. Each entry in the
table is color coded with reference to the New Low Noise Model (NLNM, Peterson, 1993):
navy, -6 db < value-NLNM < -3 db
blue, -3 db < value-NLNM < 3 db
aqua, 3 db < value-NLNM < 6 db
lime, 6 db < value-NLNM < 9 db
yellow, 9 db < value-NLNM < 12 db
orange, 12 db < value-NLNM < 15 db
red, 15 db < value-NLNM < 20 db
fuchsia, 20 db < value-NLNM < 25 db
silver, value-NLNM < -6 db, value-NLNM > 25 db
Black indicates that there was an insufficient number of hourly measurements to calculate a noise level.
| Month | Chan. | Qual. | # obs. | 518s | 439s | 373s | 316s | 268s | 228s | 193s | 164s | 139s | 118s | 100s | 85s | 72s | 61s | 52s | 44s | 37s | 32s | 27s | 23s | 19s | 16s | 14s | 12s | 10s |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 202404 | LHZ-00 | AR | 612 | -177 | -177 | -181 | -181 | -182 | -183 | -183 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -181 | -181 | -181 | -180 | -179 | -174 | -166 | -159 | -157 | -156 | -144 |
| 202403 | LHZ-00 | AR | 740 | -177 | -177 | -181 | -181 | -182 | -183 | -182 | -182 | -181 | -179 | -179 | -179 | -180 | -180 | -181 | -181 | -182 | -181 | -178 | -173 | -163 | -157 | -156 | -157 | -143 |
| 202402 | LHZ-00 | AR | 696 | -176 | -178 | -181 | -181 | -182 | -183 | -182 | -181 | -180 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -182 | -181 | -179 | -172 | -163 | -157 | -156 | -156 | -143 |
| 202401 | LHZ-00 | AR | 699 | -175 | -176 | -179 | -180 | -181 | -182 | -181 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -181 | -179 | -172 | -164 | -158 | -156 | -156 | -145 |
| 202312 | LHZ-00 | AR | 742 | -175 | -176 | -179 | -178 | -181 | -181 | -181 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -182 | -182 | -181 | -180 | -177 | -173 | -165 | -159 | -157 | -158 | -149 |
| 202311 | LHZ-00 | AR | 689 | -179 | -180 | -183 | -183 | -185 | -185 | -185 | -184 | -183 | -183 | -182 | -183 | -183 | -184 | -184 | -185 | -184 | -183 | -181 | -178 | -171 | -165 | -162 | -162 | -154 |
| 202310 | LHZ-00 | AR | 737 | -179 | -179 | -183 | -183 | -184 | -185 | -185 | -184 | -182 | -181 | -182 | -182 | -183 | -183 | -184 | -184 | -184 | -183 | -180 | -175 | -169 | -162 | -160 | -160 | -149 |
| 202309 | LHZ-00 | AR | 169 | -179 | -180 | -182 | -182 | -183 | -185 | -184 | -185 | -183 | -182 | -181 | -182 | -183 | -183 | -184 | -183 | -181 | -180 | -179 | -176 | -170 | -163 | -161 | -160 | -155 |
| 202305 | LHZ-00 | AR | 1 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| 202304 | LHZ-00 | AR | 21 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| 202303 | LHZ-00 | AR | 707 | -178 | -178 | -182 | -182 | -183 | -183 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -182 | -182 | -182 | -182 | -181 | -179 | -175 | -167 | -159 | -156 | -157 | -151 |
| 202302 | LHZ-00 | AR | 672 | -177 | -177 | -181 | -181 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -181 | -181 | -181 | -181 | -179 | -173 | -165 | -158 | -157 | -156 | -144 |
| 202301 | LHZ-00 | AR | 744 | -177 | -176 | -179 | -179 | -180 | -181 | -181 | -180 | -179 | -178 | -178 | -178 | -179 | -180 | -180 | -181 | -181 | -180 | -177 | -171 | -164 | -158 | -156 | -156 | -143 |
| 202212 | LHZ-00 | AR | 742 | -178 | -178 | -182 | -181 | -183 | -184 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -181 | -182 | -182 | -181 | -181 | -179 | -174 | -165 | -159 | -157 | -159 | -152 |
| 202211 | LHZ-00 | AR | 720 | -178 | -178 | -181 | -181 | -182 | -183 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -180 | -181 | -182 | -182 | -181 | -180 | -175 | -167 | -159 | -157 | -157 | -149 |
| 202210 | LHZ-00 | AR | 704 | -178 | -178 | -182 | -181 | -182 | -183 | -182 | -181 | -180 | -179 | -178 | -179 | -180 | -181 | -181 | -182 | -182 | -181 | -180 | -176 | -168 | -159 | -156 | -157 | -149 |
| 202209 | LHZ-00 | AR | 718 | -176 | -176 | -179 | -180 | -181 | -181 | -181 | -180 | -179 | -178 | -177 | -178 | -178 | -179 | -179 | -179 | -179 | -178 | -176 | -172 | -164 | -158 | -156 | -155 | -146 |
| 202208 | LHZ-00 | AR | 741 | -175 | -176 | -180 | -180 | -181 | -182 | -181 | -181 | -180 | -178 | -179 | -179 | -180 | -180 | -180 | -181 | -180 | -180 | -178 | -174 | -166 | -159 | -155 | -155 | -147 |
| 202207 | LHZ-00 | AR | 737 | -176 | -176 | -180 | -179 | -181 | -182 | -182 | -180 | -179 | -178 | -179 | -179 | -180 | -181 | -181 | -181 | -182 | -181 | -180 | -175 | -166 | -159 | -156 | -156 | -145 |
| 202206 | LHZ-00 | AR | 692 | -178 | -178 | -182 | -181 | -183 | -183 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -181 | -181 | -182 | -181 | -181 | -180 | -175 | -167 | -161 | -158 | -157 | -153 |
| 202205 | LHZ-00 | AR | 742 | -177 | -178 | -181 | -181 | -182 | -182 | -182 | -181 | -180 | -178 | -178 | -179 | -180 | -181 | -181 | -181 | -182 | -181 | -179 | -173 | -165 | -158 | -156 | -155 | -143 |
| 202204 | LHZ-00 | AR | 718 | -178 | -178 | -182 | -181 | -182 | -183 | -182 | -181 | -179 | -178 | -178 | -178 | -179 | -180 | -181 | -181 | -181 | -181 | -179 | -175 | -166 | -158 | -156 | -156 | -144 |
| 202203 | LHZ-00 | AR | 743 | -178 | -178 | -182 | -181 | -183 | -183 | -182 | -181 | -180 | -178 | -178 | -179 | -180 | -180 | -181 | -181 | -181 | -181 | -179 | -174 | -166 | -158 | -156 | -157 | -147 |
| 202202 | LHZ-00 | AR | 672 | -178 | -178 | -182 | -181 | -183 | -183 | -183 | -182 | -180 | -179 | -180 | -180 | -180 | -181 | -182 | -182 | -181 | -181 | -179 | -173 | -165 | -158 | -157 | -158 | -148 |
| 202201 | LHZ-00 | AR | 739 | -178 | -178 | -182 | -181 | -182 | -183 | -183 | -182 | -180 | -180 | -179 | -179 | -180 | -181 | -181 | -181 | -181 | -181 | -178 | -174 | -167 | -160 | -158 | -159 | -153 |
| 202112 | LHZ-00 | AR | 744 | -179 | -178 | -182 | -181 | -183 | -184 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -182 | -182 | -182 | -182 | -181 | -180 | -175 | -168 | -161 | -158 | -159 | -154 |
| 202111 | LHZ-00 | AR | 720 | -179 | -179 | -182 | -182 | -183 | -184 | -183 | -182 | -181 | -180 | -180 | -180 | -180 | -181 | -182 | -182 | -182 | -182 | -181 | -176 | -169 | -163 | -159 | -158 | -155 |
| 202110 | LHZ-00 | AR | 744 | -178 | -177 | -180 | -180 | -181 | -182 | -182 | -180 | -179 | -178 | -178 | -178 | -179 | -180 | -180 | -181 | -181 | -181 | -179 | -175 | -167 | -160 | -156 | -157 | -150 |
| 202109 | LHZ-00 | AR | 720 | -176 | -176 | -180 | -180 | -181 | -181 | -181 | -180 | -179 | -177 | -177 | -177 | -178 | -179 | -179 | -179 | -179 | -178 | -177 | -173 | -166 | -159 | -157 | -156 | -146 |
| 202108 | LHZ-00 | AR | 744 | -174 | -175 | -179 | -179 | -180 | -181 | -181 | -180 | -178 | -177 | -177 | -177 | -178 | -178 | -178 | -178 | -178 | -177 | -176 | -173 | -167 | -160 | -157 | -156 | -150 |
| 202107 | LHZ-00 | AR | 742 | -174 | -174 | -179 | -178 | -180 | -181 | -181 | -179 | -178 | -177 | -177 | -177 | -178 | -179 | -180 | -180 | -181 | -181 | -180 | -174 | -165 | -158 | -156 | -156 | -144 |
| 202106 | LHZ-00 | AR | 720 | -175 | -176 | -180 | -180 | -182 | -182 | -181 | -180 | -179 | -178 | -178 | -178 | -179 | -180 | -181 | -181 | -181 | -181 | -179 | -175 | -166 | -160 | -157 | -156 | -144 |
| 202105 | LHZ-00 | AR | 744 | -177 | -177 | -181 | -181 | -182 | -182 | -182 | -181 | -179 | -178 | -178 | -178 | -179 | -180 | -180 | -181 | -180 | -180 | -178 | -173 | -164 | -158 | -156 | -156 | -145 |
| 202104 | LHZ-00 | AR | 720 | -177 | -176 | -180 | -180 | -181 | -181 | -181 | -180 | -179 | -178 | -177 | -178 | -179 | -180 | -180 | -181 | -181 | -181 | -179 | -173 | -165 | -158 | -157 | -156 | -144 |
| 202103 | LHZ-00 | AR | 742 | -178 | -178 | -182 | -181 | -183 | -183 | -183 | -182 | -181 | -179 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -181 | -179 | -175 | -166 | -158 | -156 | -157 | -146 |
| 202102 | LHZ-00 | AR | 672 | -178 | -178 | -182 | -180 | -182 | -183 | -183 | -182 | -180 | -179 | -179 | -179 | -179 | -180 | -180 | -180 | -180 | -179 | -177 | -172 | -164 | -157 | -157 | -158 | -148 |
| 202101 | LHZ-00 | AR | 743 | -176 | -174 | -157 | -168 | -178 | -180 | -177 | -177 | -177 | -164 | -176 | -174 | -165 | -172 | -166 | -169 | -168 | -168 | -168 | -167 | -161 | -157 | -157 | -154 | -141 |
| 202012 | LHZ-00 | AR | 744 | -178 | -177 | -163 | -169 | -181 | -180 | -180 | -179 | -179 | -167 | -176 | -176 | -171 | -176 | -172 | -175 | -173 | -173 | -173 | -171 | -165 | -160 | -159 | -159 | -149 |
| 202011 | LHZ-00 | AR | 720 | -177 | -176 | -176 | -179 | -181 | -182 | -182 | -181 | -178 | -176 | -178 | -177 | -177 | -179 | -179 | -179 | -180 | -180 | -179 | -175 | -168 | -160 | -157 | -158 | -151 |
| 202010 | LHZ-00 | AR | 742 | -177 | -177 | -180 | -179 | -180 | -179 | -181 | -181 | -179 | -178 | -177 | -178 | -178 | -178 | -179 | -179 | -179 | -179 | -177 | -175 | -168 | -160 | -158 | -158 | -152 |
| 202009 | LHZ-00 | AR | 718 | -175 | -174 | -177 | -176 | -177 | -176 | -177 | -179 | -177 | -177 | -176 | -176 | -175 | -175 | -176 | -175 | -175 | -175 | -175 | -172 | -165 | -158 | -156 | -156 | -145 |
| 202008 | LHZ-00 | AR | 738 | -176 | -176 | -179 | -177 | -179 | -179 | -180 | -181 | -180 | -178 | -177 | -178 | -177 | -178 | -179 | -178 | -179 | -178 | -177 | -175 | -168 | -160 | -157 | -157 | -152 |
| 202007 | LHZ-00 | AR | 740 | -176 | -177 | -181 | -180 | -182 | -183 | -182 | -182 | -181 | -180 | -179 | -180 | -180 | -180 | -181 | -180 | -181 | -180 | -179 | -175 | -168 | -162 | -159 | -158 | -156 |
| 202006 | LHZ-00 | AR | 716 | -176 | -176 | -181 | -180 | -182 | -182 | -181 | -180 | -179 | -177 | -178 | -177 | -178 | -179 | -180 | -181 | -181 | -180 | -179 | -175 | -167 | -158 | -156 | -155 | -144 |
| 202005 | LHZ-00 | AR | 744 | -178 | -177 | -181 | -180 | -182 | -183 | -182 | -181 | -180 | -179 | -178 | -178 | -179 | -180 | -180 | -180 | -180 | -180 | -178 | -174 | -167 | -159 | -156 | -155 | -149 |
| 202004 | LHZ-00 | AR | 717 | -177 | -178 | -182 | -182 | -183 | -183 | -183 | -182 | -180 | -179 | -179 | -180 | -180 | -181 | -181 | -181 | -181 | -180 | -179 | -175 | -166 | -159 | -158 | -157 | -150 |
| 202003 | LHZ-00 | AR | 744 | -177 | -177 | -181 | -181 | -182 | -183 | -182 | -181 | -179 | -178 | -178 | -179 | -180 | -181 | -181 | -181 | -181 | -181 | -180 | -175 | -166 | -158 | -156 | -157 | -145 |
| 202002 | LHZ-00 | AR | 686 | -179 | -179 | -182 | -181 | -183 | -183 | -183 | -181 | -180 | -179 | -179 | -180 | -180 | -182 | -182 | -182 | -182 | -182 | -180 | -176 | -166 | -159 | -157 | -158 | -148 |
| 202001 | LHZ-00 | AR | 744 | -178 | -177 | -181 | -180 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -181 | -181 | -181 | -180 | -178 | -173 | -165 | -158 | -157 | -157 | -146 |
| 201912 | LHZ-00 | AR | 728 | -179 | -179 | -182 | -182 | -183 | -183 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -182 | -182 | -182 | -182 | -182 | -180 | -174 | -166 | -159 | -158 | -159 | -151 |
| 201911 | LHZ-00 | AR | 576 | -178 | -178 | -182 | -181 | -184 | -183 | -183 | -182 | -181 | -179 | -180 | -179 | -181 | -181 | -182 | -182 | -182 | -181 | -180 | -175 | -168 | -162 | -158 | -158 | -152 |
| 201910 | LHZ-00 | AR | 581 | -178 | -178 | -182 | -182 | -183 | -184 | -183 | -182 | -180 | -179 | -180 | -180 | -180 | -181 | -181 | -181 | -182 | -181 | -179 | -175 | -168 | -161 | -158 | -158 | -153 |
| 201909 | LHZ-00 | AR | 716 | -178 | -179 | -183 | -181 | -183 | -184 | -184 | -182 | -181 | -180 | -179 | -179 | -180 | -181 | -181 | -181 | -181 | -180 | -179 | -173 | -165 | -160 | -157 | -156 | -148 |
| 201908 | LHZ-00 | AR | 729 | -177 | -177 | -182 | -181 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -180 | -180 | -180 | -180 | -179 | -177 | -173 | -167 | -159 | -156 | -156 | -150 |
| 201907 | LHZ-00 | AR | 734 | -175 | -175 | -179 | -179 | -181 | -182 | -181 | -180 | -179 | -177 | -178 | -178 | -179 | -179 | -180 | -180 | -180 | -180 | -178 | -173 | -165 | -158 | -157 | -156 | -148 |
| 201906 | LHZ-00 | AR | 716 | -176 | -176 | -180 | -179 | -181 | -182 | -181 | -180 | -179 | -178 | -178 | -177 | -178 | -179 | -179 | -178 | -178 | -177 | -176 | -172 | -165 | -159 | -156 | -156 | -147 |
| 201905 | LHZ-00 | AR | 741 | -176 | -176 | -179 | -179 | -181 | -181 | -181 | -180 | -179 | -178 | -177 | -178 | -178 | -179 | -179 | -180 | -180 | -180 | -178 | -173 | -165 | -158 | -155 | -154 | -141 |
| 201904 | LHZ-00 | AR | 662 | -179 | -179 | -182 | -182 | -183 | -183 | -183 | -182 | -180 | -179 | -179 | -179 | -180 | -181 | -182 | -182 | -182 | -181 | -179 | -174 | -166 | -159 | -156 | -156 | -149 |
| 201903 | LHZ-00 | AR | 740 | -179 | -179 | -182 | -181 | -183 | -184 | -183 | -182 | -180 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -182 | -181 | -179 | -173 | -164 | -158 | -157 | -157 | -149 |
| 201902 | LHZ-00 | AR | 660 | -178 | -178 | -181 | -181 | -182 | -183 | -183 | -182 | -181 | -180 | -180 | -180 | -181 | -182 | -182 | -182 | -182 | -182 | -180 | -174 | -165 | -158 | -157 | -158 | -151 |
| 201901 | LHZ-00 | AR | 738 | -178 | -178 | -182 | -181 | -182 | -183 | -182 | -182 | -180 | -179 | -179 | -179 | -181 | -181 | -182 | -182 | -182 | -181 | -179 | -174 | -165 | -158 | -158 | -158 | -146 |
| 201812 | LHZ-00 | AR | 740 | -178 | -177 | -181 | -180 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -182 | -182 | -182 | -182 | -179 | -172 | -164 | -159 | -158 | -156 | -146 |
| 201811 | LHZ-00 | AR | 708 | -177 | -177 | -180 | -180 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -182 | -182 | -182 | -182 | -180 | -176 | -168 | -161 | -158 | -157 | -152 |
| 201810 | LHZ-00 | AR | 738 | -177 | -177 | -181 | -180 | -182 | -182 | -182 | -181 | -180 | -179 | -178 | -179 | -180 | -181 | -181 | -181 | -182 | -181 | -179 | -173 | -165 | -159 | -157 | -156 | -145 |
| 201809 | LHZ-00 | AR | 708 | -176 | -176 | -181 | -181 | -182 | -182 | -182 | -181 | -180 | -179 | -179 | -179 | -179 | -180 | -180 | -180 | -180 | -180 | -178 | -173 | -164 | -159 | -156 | -155 | -145 |
| 201808 | LHZ-00 | AR | 720 | -176 | -176 | -180 | -180 | -182 | -183 | -182 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -182 | -180 | -176 | -167 | -160 | -157 | -157 | -150 |
| 201807 | LHZ-00 | AR | 736 | -176 | -176 | -180 | -180 | -182 | -182 | -181 | -181 | -180 | -179 | -178 | -179 | -179 | -180 | -180 | -181 | -181 | -180 | -178 | -174 | -166 | -159 | -157 | -156 | -148 |
| 201806 | LHZ-00 | AR | 709 | -175 | -175 | -179 | -179 | -181 | -181 | -181 | -180 | -179 | -178 | -178 | -178 | -178 | -179 | -179 | -180 | -180 | -179 | -178 | -174 | -167 | -160 | -155 | -156 | -147 |
| 201805 | LHZ-00 | AR | 718 | -177 | -177 | -181 | -181 | -183 | -183 | -183 | -182 | -180 | -179 | -179 | -179 | -180 | -181 | -180 | -180 | -180 | -180 | -177 | -172 | -166 | -159 | -157 | -156 | -149 |
| 201804 | LHZ-00 | AR | 705 | -177 | -178 | -181 | -181 | -182 | -183 | -182 | -180 | -180 | -178 | -178 | -178 | -179 | -181 | -181 | -182 | -182 | -181 | -180 | -176 | -168 | -161 | -158 | -158 | -151 |
| 201803 | LHZ-00 | AR | 728 | -177 | -177 | -181 | -180 | -182 | -183 | -182 | -181 | -180 | -179 | -178 | -179 | -180 | -181 | -181 | -181 | -181 | -181 | -179 | -175 | -166 | -158 | -156 | -157 | -148 |
| 201802 | LHZ-00 | AR | 660 | -178 | -178 | -182 | -182 | -183 | -183 | -182 | -182 | -180 | -179 | -179 | -180 | -181 | -181 | -182 | -182 | -182 | -182 | -181 | -176 | -167 | -160 | -157 | -157 | -153 |
| 201801 | LHZ-00 | AR | 730 | -178 | -177 | -181 | -181 | -182 | -183 | -183 | -181 | -180 | -179 | -179 | -179 | -180 | -181 | -182 | -182 | -182 | -181 | -179 | -174 | -167 | -161 | -158 | -160 | -157 |